Apparatus and method for fractionating alternative solid fuels

Abstract

An apparatus and a method fractionate solid fuels, especially whole tires, into metal as well as volatiles and coal to be used as alternative fuels. The apparatus includes a feeding zone wherein the solid fuels are fed to the apparatus, a gasifying zone into which the solid fuels are processed, obtaining a gaseous fraction, coal, and metal; cooled grills controlling the bed permeability and permanence time of the solid fuels at the gasifying zone; and a discharging zone into which the resultant coal and metal are discharged, in which the solid fuel coal and solid and gaseous fractions follow a path inside the apparatus through the feeding zone, the gasifying zone and discharging zone, and in which the gases inside the apparatus follow a path that is co-current with the solid fuel fractions path inside the apparatus.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/389,851, filed Sep. 2, 1999, now abandoned.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an apparatus and a method for the recovery of energy from solid waste by combustion of the solid waste in industrial kilns, and more particularly to an apparatus and a method for fractionating alternative solid fuels, especially tires, into metal as well as volatile gases and coal to be used as alternative fuels.

[0004] 2. Description of the Related Art

[0005] Since 1980, hazardous solid wastes, such as discarded tires from many kinds of vehicles, have been used as alternative or supplemental fuel in kilns for the production of cement.

[0006] The necessity of reducing total fuel costs through the substitution of waste-derived fuels instead of normal fossil fuels, primarily coal, has been the main incentive behind the search of cheap alternative fuels to fire industrial kilns such as kilns for producing cement.

[0007] The most readily usable non-hazardous wastes having the highest heat content consist of discarded tires. It is estimated that there are about 36 cement plants in the United States utilizing tire-derived fuel.

[0008] Whole tires, tires ground into “crumb”, and tire chips are used as fuel with essentially similar results.

[0009] Tires grounded into “crumb” have the following advantages: 1) the generation of the crumb from the tires allows the steel in the bead and radial bands to be removed by air classification; 2) the crumb can be blown inside the kiln together with powdered coal fuel, thus substituting a part of the powdered coal as the main fuel source; and 3) the transportation storage and management of the crumb is very similar to the managing of coal fines.

[0010] There are however some disadvantages when using crumb for producing cement: 1) the removal of steel wires from crumb is very difficult, notwithstanding that processes for producing cement need iron; and 2) producing crumb is quite expensive, giving the crumb a price as high as coal or coke.

[0011] Tires “chips” of many sizes are normally used as fuel in kilns for producing cement. These chips range in sizes varying from 2 cm.×2 cm. to 15 cm.×15 cm. For any chip size, the transportation, storage, and management costs are essentially the same. Transportation is carried out by truck, and chips are accumulated in large piles in the open, similar to the storage methods of coal or limestone. The feeding of the chips into the kiln is carried out by means of a conveyor fed from a hopper. A front end loader is used to load the hopper from the storage pile.

[0012] The use of tire chips as fuel has some advantages: 1) the feed rate may be continuously monitored and carefully controlled; and 2) there is very little manual labor involved in handling chips versus whole tires.

[0013] There are, however, some disadvantages when using tire chips: 1) the production of chips from whole tires is expensive, certainly not as costly as the production of crumb, but production often represents half the cost of acquiring and delivering the supplemental fuel; and 2) the steel wire from the bead and radial belts of the tires does not shear off smoothly when the tires are chipped, and consequently the chips are ragged and the steel wires may hook everything they come into contact with, making the facility operation difficult.

[0014] The use of whole tires as fuel in kilns for producing cement is also common in the cement industry. Tires are delivered by trucks at the end of a conveyor, and then tires are manually unloaded from the truck onto the conveyor. The conveyor feeds the tires to a mechanism that inserts one tire at a time into the kiln at specified time intervals. The main advantage of using whole tires is that there are no processing costs in addition to the acquisition costs. In addition, unlike tire chips, the whole tires do not “fly” throughout the facility nor have the possibility of causing possible “dust fires”, like the crumb.

[0015] However, despite the above advantages, the use of whole tires generates some problems related to the removal of steel wire from the gasifier section of the kiln, in which the steel wire tends to get entangled into the gasifier, forming a great tangle of wire, affecting the flow of volatiles from the combustion chamber to the kiln or calcinator, decreasing the fuel substitution percentage and limiting the use of whole tires as supplemental fuel.

[0016] Therefore, since whole tires are the most reliable and economic alternative fuel, it would be highly desirable to have a method and apparatus that could solve the above referred problems.

[0017] In recent years, there have been developed a number of methods and apparatuses for the recovery of energy from waste material, especially for kilns for producing cement, which are specially adapted to use tires (both grounded or whole tires) as a fuel substitute in the range of 5% to 25% at best, depending on the type of kiln, fuel, and feeding points.

[0018] U.S. Pat. No. 4,627,877 to Ogawa et al. discloses a method and apparatus for continuously producing a cement clinker by using a waste material as a fuel for preheating or calcinating a cement material, by using an apparatus comprising a cement material feeder, a preheater or calcinator, a rotary kiln, a cooler, and means for flowing an exhaust gas from the rotary kiln to the preheater or calcinator. The apparatus is characterized by including a heat-decomposer which is located between the preheater or calcinator and the rotary kiln, in which a combustible material is heat decomposed by a hot gas exhausted from the rotary kiln and the resultant combustible gas is burnt in the preheater or calcinator substituting a part of the primary fuel therein. Ogawa's method has the limitation that it is only able to use grounded tires since it does not have any means to prevent entanglements of wire or means to remove the wire which is released when using whole tires. Furthermore, Ogawa's method does not show any means to control the bed permeability and permanence of the grounded tire at the calcination point which would be highly desirable since controlling the permanence time and permeability of the bed will allow a complete calcination of the tire and an adequate production and flow of the volatiles to the point of combustion.

[0019] U.S. Pat. No. 4,640,681 to Steinbiss et al. discloses a method and apparatus for the disposition of hazardous and waste materials of low heat content, for example, refuse, by means of a combustion process which is carried out in a furnace, by the presence of added hot combustion air at a sufficient temperature so that the combustion and/or flue gas temperatures are at least 1,250° C.

[0020] In a preferred embodiment of the invention, the combustion process is combined with a process for the production of cement clinker and is carried out parallel to the same, wherein air at about 800° C. is branched off for combustion of the hazardous substances from the cooler air of the cement clinker installation and introduced into the furnace. The hot flue gas of the combustion in the furnace is directed into the cement clinker installation.

[0021] Although in the Steinbiss patent it is possible to control the permanence time of the waste materials in the furnace, this method and apparatus is not intended for whole tires and it is a fluidized bed gasifier. Therefore it can not gasify whole tires and discharge the wire. Furthermore, since the main objective of this invention is the disposition of hazardous and waste materials, it is designed to use only waste materials of low heat content, therefore the quality and quantity of volatile produced is very low and cannot be considered as a suitable supplemental fuel for industrial kilns.

[0022] Furthermore, it is clear that the Steinbiss apparatus is not designed to efficiently gasify materials due to the following reasons:

[0023] 1. The operating temperature of the Steinbiss apparatus and method would produce liquid phases of the materials which would adhere to the furnace walls.

[0024] 2. The Steinbiss apparatus and method neither teach nor disclose a method for continuously discharging the waste material.

[0025] 3. The Steinbiss grate does not disclose cooling means for avoiding the melting of material on the grate.

[0026] U.S. Pat. No. 5,636,581 of Kleen discloses: a plurality of fluid-cooled grate bars, each said grate bar having a duct extending substantially longitudinally therewithin for guiding a first coolant, each said duct having an inlet and outlet opening for feeding and discharging the first coolant, said plurality of grate bars being arranged in adjacent alternately stationary and moveable rows; and a main fluid inlet line and a main fluid outlet line, each said inlet and outlet opening of each said duct of each said grate bar being connected with said main fluid inlet line and said main fluid outlet line, respectively, wherein said plural grate bars are connected in parallel to the main fluid inlet line and the main fluid outlet line for fluid communication therewith.

[0027] It should be noted that Kleen's cooled grate is unable to handle the wire from whole tires because Kleen's cooled grill is intended to be used in garbage incinerators, having adjacent rows of alternately stationary and mobile grate bars and it does not disclose or even suggest any structural element that is capable of preventing the entanglement of wire when burning tires. Furthermore, the purpose of the cooling means of Kleen's grill is to cool the grate in order to minimize wearing of the grate and avoiding structural collapse. The cooling means are not designed nor are they capable of lowering the temperature of the gate surface so as to avoid the melting of material on the grate.

[0028] U.S. Pat. No. 4,256,503 to Tsuda et al. discloses a method for effectively utilizing waste tires in an apparatus for burning cement by means of a rotary kiln, comprising the steps of; charging waste tires crushed or without crushing as fuel directly into the back end of the kiln, to a position in said kiln wherein the gas temperature is 600° C. to 1,400° C., in an amount not exceeding 60% of the total fuel calculated as heat energy. The main disadvantage of this method is that the heat released by the combustion of volatiles would overheat the back end of the kiln and would induce the formation of very hard agglomerates which are very difficult to remove.

[0029] U.S. Pat. No. 4,110,121 to Rechmeir et al. discloses a process for producing cement clinker in which raw meal is fed to a heat exchanger, heat is supplied to the heat exchanger from a downstream kiln, the raw meal is heated in the heat exchanger and the heated raw meal is conveyed to the kiln and sintered therein by the use of a fuel to form the cement clinker, the improvement comprises using high grade waste fuel formed from organic waste in the form of tires, rubber scrap, or plastics scrap and wherein the waste fuel is processed before combustion by pyrolysis to form pyrolysis gases and a pyrolyzed residue and said pyrolyzed residue is comminuted or gasified. Although the Rechmeir process discloses the separation of the residual carbon form tires, it does not disclose the separation of the wire or the management of the wire into the pyrolyzer, which would limit the use of whole tires.

[0030] U.S. Pat. No. 5,226,774 to Tutt et al. discloses an apparatus for controlling the input of combustible solids through a port formed in a wall of a rotary kiln cylinder of an operating cement kiln at a location between an upper end and a lower fired end thereof, the kiln containing hot mineral material for combustion of said combustible solids in contact with said mineral material. In Tutt's apparatus, the tires are directly feed into the kiln, and therefore the disadvantages are similar to those of Tsuda's method.

[0031] U.S. Pat. No. 4,627,877 to Ogawa et al. discloses a method and apparatus for continuously producing a cement clinker comprising the steps of: feeding a cement material into a preheating or calcinating region; preheating or calcinating said fed cement material in a predetermined temperature range; forwarding said preheated or calcinated cement material into a heating region; heating said preheated or calcinated cement material at a predetermined temperature to convert said cement material to a cement clinker; moving said cement clinker into a cooling region; cooling said cement clinker with cooling air to a decreased temperature, and; flowing an exhaust gas from said heating region through said preheating or calcinating region, which method is characterized by the steps of: feeding a combustible material into a heat-decomposing region located between said heating region and said preheating or calcinating region; introducing at least a portion of said exhaust gas from said heating region into said heat-decomposing region to heat-decompose said combustible material and to generate a combustible gas therefrom; introducing said combustible gas from said heat-decomposing region into said preheating or calcinating region, and; burning said combustible gas in said preheating or calcinating region to preheat or calcinate said cement material.

[0032] If there were applied cooled grills (as in Kleen's patent) under the operating conditions of Ogawa's method, the kiln gas would flow countercurrent to the feeding path through the gasifying zone, thus causing low melting compounds carried by the kiln gas (Na2O, Na2SO4, K2SO4, etc) to go up and solidify and form mineral deposits on the grill. Such deposits would avoid the movement of the cooled grill for discharging the wire.

[0033] Furthermore, since the hot kiln gas would reach the cooled grills, the wire would frequently melt on the grill and on the refractory walls.

BRIEF SUMMARY OF THE INVENTION

[0034] Applicant carried out several tests in bench scale models using countercurrent models and the melting of the wire happened twice as many times as the co-current model. Therefore, it is much easier to control the gasifier to minimize wire melting when it is operated with the air flowing concurrently with the solid fuel.

[0035] The change from countercurrent to co-current is very important since a person having an ordinary skill in the art would say that a countercurrent gasifier is kinetically and thermodynamically superior than a co-current one. However, in view of the results obtained by applicant's experiments, one can conclude that the co-current model has advantages over the prior art countercurrent model.

[0036] Since chemical engineers know that a countercurrent heat exchanger is more efficient than a co-current one, the fact that a co-current gasifier has advantages over a countercurrent one has to be proved by means of experimentation. The aforesaid experimentation shows that the development of the co-current concept and model is not obvious.

[0037] Therefore, if a person skilled in the art propose to combine Steinbiss's, Ogawa's and Kleen's designs in order to produce an apparatus for gasifying whole tires, the resulting design would not work properly because the countercurrent model causes the melting of the wire on the cooled grill. Also, the use of hot gas form the kiln, carrying low melting point compounds produce build ups on the cooled grills that causes a lot of operation problems.

[0038] Finally, it should be noted that:

[0039] 1. None of the apparatuses and methods disclosed in the Steinbiss, Kleen and Ogawa patents are capable of continuously fractionating whole tires while discharging the wire thereof, without entangling the wire inside the apparatus, and while achieving a fuel substitution of greater than 10%.

[0040] 2. None of the references disclose the capability of avoiding hot spots, reducing atmospheres and build-ups which are observed when the coal and wire are discharged in the kiln after the combustion of whole tires.

[0041] Note should also be taken that even considering the combination of the above referred patents, they do not teach, disclose or suggest how to achieve an apparatus for fractionating alternative solid fuels (especially whole tires) having the following characteristics:

[0042] 1. Having the capacity of continuously fractionating whole tires without wire entanglements due to the mesh which allows for the continuous discharge of wire from the apparatus.

[0043] 2. Wherein the mesh for controlling the residence time of the material to be burned at the gasifying zone have cooling means for cooling the surface of the gates and avoiding the melting of the material on the gate when burned.

[0044] 3. Capability of achieving a fuel substitution percentage of greater than 10%, without the formation of build-ups.

[0045] 4. Ability to avoid secondary effects, such as the formation of hot spots or reducing atmospheres.

[0046] 5. Easily adaptable to any type of industrial kiln.

[0047] Considering the above referred problems, applicants developed an apparatus and a method for fractionating alternative solid fuels, especially whole tires, into volatiles and coal, to be used as alternative fuels, and metal, which uses the co-current model.

[0048] Applicant's apparatus and method provide means to separate the residual carbon and volatile of burned solid fuels, as well as the wire produced by the combustion of the whole tires. Furthermore, there are included means to control the permanence time of the solid fuel at the gasifying zone of the apparatus, which can be optimized for each type of solid fuel.

[0049] Applicant's apparatus comprises a main column having a feeding zone, including one or more feeding valves; a hot air input, providing a hot air current that follows the same path as the solid fuels inside the gasifier; driving means are provided for opening and closing said feeding valves; a gasifying zone located below the feeding zone, having a cool air input coming from a suitable source such as an air pump; If possible an input for hot air which is used for the combustion of the solid fuels, coming from a suitable source; one or more alternately introduced and withdrawn cooled grills controlling the permeability and permanence time of the solid fuels at the gasifying zone; a gasifier duct in which the volatiles are discharged from the gasifying zone to the main burner or other suitable zone of the kiln or pre-heater wherein the apparatus of the present invention will be used; a discharging zone located below the gasifying zone having one ore more discharging valves which receive the coal and solids coming from the gasifier and which are opened at a convenient time in order to discharge the coal and solids from the apparatus; and a discharging opening situated below the discharging valves.

[0050] Applicant's apparatus uses the co-current model in which the air follows the same direction as the solid fuels inside the gasifier, avoiding the return of hot air form the kiln carrying low melting point compounds which may solidify on the cooled grills and avoiding the melting of wire on the cooled grills and on the walls of the gasifier.

[0051] Applicant's method comprises: providing an apparatus including a gasifier wherein the solid fuels will be partially burned and the volatiles will be emitted; feeding the alternative solid fuel to the gasifying zone of the apparatus; providing a hot air current that follows the same path as the solid fuels inside the gasifier; providing cool air to the gasifier and if possible hot air from a suitable source; partially burning the alternative solid fuels into the gasifying zone until most of the volatiles have been emitted, coal with a minimum content of volatiles is obtained, and the non combustible solids are separated; discharging the volatiles from the gasifier for further use; and discharging the resultant coal and solids from the gasifier by gravity or any other known means.

[0052] With applicant's apparatus and method, the fuel substitution percentage achieved can be higher than 40%, which is higher than the fuel substitution percentages achieved by the actual known methods and apparatuses.

[0053] It is therefore a main objective of the present invention, to provide an apparatus and a method for fractionating alternative solid fuels that uses the air flow co-current model inside the gasifier.

[0054] It is also a main objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above disclosed nature, which provide means to separate the volatiles and the residual coal, to be used as alternative fuels, and the non combustible solids, produced by the partial combustion of the solid fuels.

[0055] It is another objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above disclosed nature, which provide means to separate the wire produced by the combustion of whole tires.

[0056] It is also a main objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above disclosed nature, which include means to control the permanence time of the solid fuel at the calcination point, to be optimized for each type of solid fuel.

[0057] It is still another objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above disclosed nature which includes means for controlling permeability.

[0058] It is still a main objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above disclosed nature, in which fuel substitution percentage achieved is higher than 40%, which is higher than the fuel substitution percentages achieved by the actual methods and apparatuses.

[0059] These and other objects and advantages of the apparatus and method for fractionating alternative solid fuels, of the present invention will become apparent to those persons having an ordinary skill in the art, from the following detailed description of the embodiments of the invention which will be made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0060] FIG. 1 is a front view of the apparatus for fractionating alternative solid fuels of the present invention.

[0061] FIG. 2 is a diagram of a cement plant, including the apparatus for fractionating alternative solid fuels of the present invention in a first embodiment of use.

[0062] FIG. 3 is a diagram of a cement plant, including the apparatus for fractionating alternative solid fuels of the present invention in a second embodiment of use.

[0063] FIG. 4 is a diagram of a cement plant, including the apparatus for fractionating alternative solid fuels of the present invention in a third embodiment of use.

[0064] FIG. 5 is a diagram of a cement plant, including the apparatus for fractionating alternative solid fuels of the present invention in a fourth embodiment of use.

[0065] FIG. 6 is a diagram of a cement plant, including the apparatus for fractionating alternative solid fuels of the present invention in a fifth embodiment of use.

[0066] FIG. 7 is a diagram of a thermoelectrical plant, including the apparatus for fractionating alternative solid fuels of the present invention as another embodiment of use.

[0067] FIG. 8 is a top view of the mesh/grill of the present invention showing the cooling means.

DETAILED DESCRIPTION OF THE INVENTION

[0068] The invention will be described referring to a preferred embodiment thereof, illustrated in the accompanying drawings wherein the same signs and numbers, refer to the same parts of the shown figures.

[0069] Referring to FIG. 1, the apparatus for fractionating alternative solid fuel includes:

[0070] gasifying means having a main column 1 having a first end 2 and a second end 3, and including:

[0071] a feeding zone F, having:

[0072] valve means including one or more feeding valves comprising gates 4, 4′, located at the feeding zone F, in which the solid fuels S are fed, and which are opened and closed for a convenient time and sequence in order to feed the solid fuels S to the place wherein the combustion will take place;

[0073] driving means for the feeding valves (not shown) which could be hydraulic motors, for opening and closing said feeding valves 4,4′;

[0074] a gasifying zone G located below the feeding zone F, having:

[0075] input means for hot air 5 which is used for the combustion of the solid fuels S, coming from a suitable source (not illustrated) which could be, in case of applying the present invention to a rotary kiln for producing cement, the tertiary air duct or the clinker cooler, with such input means providing a hot air current that is co-current with the path that follow the solid fuels inside the apparatus;

[0076] input means 6 for cool air coming from a suitable source such as an air pump;

[0077] retaining means comprising one or more alternately introduced and withdrawn cooled mesh and/or grills 7, 7′, 7″ having internal pipes P as cooling means, such as mesh 7 with pipes P shown in FIG. 8; and

[0078] driving means 20, such as motors and/or pumps, are capable of substantially and/or totally introducing and/or withdrawing the mesh and/or grills, such as grill 7 in FIG. 8, into the pathway of the materials, with substantial and/or total withdrawal allowing the processed tires to pass through the pathways of the apparatus unobstructed and to avoid build-up and/or clogging of material in the pathways, with cool air or water is circulated into the pipes P by means of a pump, said cooled grills controlling the bed permeability and permanence time of the solid fuels S at the gasifying zone G and are able to be withdrawn in order to discharge the coal and solids, after the separation of volatile and solids is achieved, to a discharging zone D avoiding the melting of wire or any matter on the grills, with the driving means 20 for the cooled grills, as shown in FIG. 8, which operatively introduce or withdraw said cooled grills 7, 7′, 7″;

[0079] a duct 8 into which volatiles are discharged from the gasifying zone G for further use, said volatiles serving as supplemental fuel;

[0080] a discharging zone D located below the gasifying zone G having:

[0081] valve means including one ore more discharging valves comprising gates 9, 9′ which receive the coal C and solids, such as wire W, coming from the gasifier G and which are opened at a convenient time in order to discharge the coal and solids C from the apparatus; and

[0082] a discharging opening H located below the discharging valves or gates 9, 9′ to discharge the coal C and solids, such as wire W, from the apparatus.

[0083] It is to be understood that the gasifying means may be a vertical column wherein the feeding zone, the gasifying zone and the discharging zone are placed in a downwardly sequence, or else, it can be a horizontal chamber wherein the feeding zone, the gasifying zone and the discharging zone are placed in a side by side fashion, and in this embodiment it would be needed a mechanical feeding device including an hydraulic cylinder and piston assembly (not shown).

[0084] The apparatus of the present invention, operating at a temperature between about 900° C. and about 1150° C., can be used for fractionating continuously batches of supplemental fuel, such as whole tires, so that when a first batch of burning material is placed at the feeding valves 4,4′ which are initially closed, a second batch may be already at the gasifying zone G, wherein the cooled grills 7, 7′, 7″ are sequentially opened at predetermined times, depending on the characteristics, such as size, of the supplemental fuel being processed, thus controlling the bed permeability and permanence time, and avoiding the formation of agglomerates inside the apparatus. The grill cooling means (not shown) avoid that the pipes forming the grill lose mechanical properties due to overheating or corrosion.

[0085] When the last cooled grill is opened 7″, if the apparatus has more than one grill, the resultant coal C and solids, such as wire W, are discharged to the discharge valve 9, which is opened at a convenient time as well as the other discharge valves 9′, in case that the apparatus has more than one discharge valve, when a predetermined amount of coal C and solids W are obtained.

[0086] The last feeding valve 4′ is opened discharging the supplemental fuel to the first cooled grill 7, as soon as this is emptied.

[0087] Therefore, the apparatus of the present invention can be fed with whole tires, without problems such as wire entangling, obtaining a complete separation of volatile, coal and wire.

[0088] Although it was mentioned that the apparatus of the present invention has an input of hot air 5, it is also suitable to operate without a hot air input when there is not available.

[0089] As it was mentioned, one of the applications of the present invention is at the cement industry, in which the installation of the present apparatus is at a rotary cement kiln or calcinator, using whole or shredded tires as supplemental fuel.

[0090] Referring to FIG. 2, a first possible embodiment of use of the apparatus of the present invention R, at a rotary cement kiln, is by installing the apparatus at the back end of the cement kiln, feeding the apparatus with whole or shredded tires T, injecting air form the atmosphere A, taking hot air from the tertiary air duct 19, if the kiln has a tertiary air duct, and discharging the volatiles V to the pre-calcinator or calcinator 10 to substitute primary fuel M, and discharging wire W and tire coal C to the kiln input 11 to substitute primary fuel. The wire is integrated to the clinker K, substituting part of the iron required in the form of an oxide. The main advantages of this form of use are that the volatiles are burned where it is required. Therefore there is less tendency to form hot points and agglomerates at the input of the kiln, than in the case in which all the alternative fuel is directly fed to the kiln.

[0091] Referring to FIG. 3, a second possible embodiment of use, is as described in the first one, but additionally discharging the wire W to the outside of the apparatus and of the rotary kiln 12, to containers or to a conveyor belt (not shown). This way of use is suitable for the production of white cement in which the iron oxide content is less than in the normal cement.

[0092] Referring to FIG. 4, a third possible embodiment of use, is as described in the second one, but discharging the tire coal C to the main burner 13. The main advantage of discharging the tire coal C to the main burner 13 is that a higher percentage of primary fuel substitution can be achieved mainly because the tire coal C is burned in the main burner 13 after reaching the limit of energy amount substituted at the pre-calcinator.

[0093] Referring to FIG. 5, a fourth possible embodiment of use consists on using the residual air from the clinker cooler 14 which is hotter than the atmosphere air, instead of using hot air from the tertiary air duct 19. The volatiles V are discharged and burned in the main burner 13 and the tire coal C is discharged to the calcinator 10, achieving a higher percentage of primary fuel substitution. In this case, the wire W is discharged outside of the apparatus and of the rotary kiln 12, to containers or to a conveyor belt (not shown). Therefore it is possible the application of the recuperator R of the present invention at kilns without a pre-calcinator.

[0094] Referring to FIG. 6, a fifth possible embodiment of use is as described in the fourth one, but discharging the tire coal C to the main burner 13. Therefore it is also possible the application of the recuperator R of the present invention at kilns without a pre-calcinator.

[0095] Referring again to FIG. 1, a sixth possible embodiment of use is as described in the first one, but, instead of using whole or shredded tires, alternative solid fuels having similar or the same properties of the tires, are used, i.e., so that a residue similar to coal be obtained.

[0096] Although it has been mentioned that the apparatus of the present invention can be used at the cement industry, it can be used at any kind of industry having industrial kilns. For example, referring to FIG. 7, it can be used at a thermoelectrical plant or any other industrial kiln, discharging the volatiles V and tire coal C to the main burner 13, and discharging the wire W to outside of the apparatus.

[0097] The method for fractionating alternative solid fuels, especially whole tires, according to the present invention comprises the steps of:

[0098] providing an apparatus including a gasifier wherein the solid fuels will be partially burned and the volatiles will be emitted;

[0099] feeding the alternative solid fuel to the gasifying zone of the apparatus;

[0100] providing cool air to the gasifier from the atmosphere and if possible hot air from a suitable source;

[0101] partially burning the alternative solid fuels into the gasifying zone until most of the volatiles have been emitted, coal with a minimum content of volatiles is obtained, and the non combustible solids are separated;

[0102] discharging the volatiles from the gasifier to an industrial kiln wherein the substitution of primary fuel will be made;

[0103] discharging the resultant coal and solids from the gasifier by gravity or any other known means to an industrial kiln wherein the substitution of primary fuel will be made or to a conveyor belt or to a container for further use.

[0104] Although it was described that it is provided hot air to the gasifier from a suitable source, it is suitable to make the combustion with cool air only.

Tests Results

[0105] During several tests carried out with a co-current model gasifier and with a countercurrent model gasifier the following results were obtained: 1 TABLE 1 Gasifier Obstructions And Percentage Of Coal Obtained Flow Flow model nl/min Gasifier obstruction % discharged coal Countercurrent 80 Negative 10.99% Countercurrent 80 Positive 11.62% Countercurrent 80 Positive 22.23% Countercurrent 90 Negative 11.54% Countercurrent 90 Positive  9.70% Countercurrent 90 Positive  9.71% Co-current 80 Negative 23.43% Co-current 80 Negative 23.37% Co-current 80 Positive 24.76% Co-current 90 Positive 26.33% Co-current 90 Negative 25.26% Co-current 90 Negative 24.90%

[0106] The above table show the test in which obstruction occurred, and the percentage of coal discharged (more discharged coal is better). 2 TABLE 2 Coal Distribution Discharged Flow model coal Sedimentation coal Recuperated coal Countercurrent 10.99% 14.10% 25.09% Countercurrent 11.62% 20.73% 32.35% Countercurrent 22.23% 16.30% 38.53% Countercurrent 11.54% 18.43% 29.97% Countercurrent  9.90% 15.48% 25.38% Countercurrent  9.71% 23.13% 32.83% Co-current 23.43%  2.06% 25.49% Co-current 23.37%  4.14% 27.51% Co-current 24.76%  3.76% 28.52% Co-current 26.33%  4.02% 30.35% Co-current 25.26%  3.04% 28.30% Co-current 24.90%  4.18% 29.08%

[0107] Table 2 shows the distribution of discharged, sedimentation and total recuperated coal (more is better). In practice, the recuperated coal would be only the discharged coal. The sedimentation coal is the coal that the gas flow captured in the sedimentation chamber. Table 2 shows that the countercurrent model produces more sedimentation coal and takes a longer time to be completely burned which is a disadvantage from the combustion standpoint.

[0108] Finally it is to be understood that the apparatus and method for fractionating alternative solid fuels of the present invention, is not limited exclusively to the above described and illustrated embodiments and that the persons having ordinary skill in the art can, with the teaching provided by this invention, to make modifications to the design and component distribution of the, apparatus and method for fractionating alternative solid fuels of the present invention, which will clearly be within the true inventive concept and scope of the invention which is claimed in the following claims.

Claims

57. An apparatus for fractionating solid fuels into a gaseous fraction, a coal fraction, and a non-coal fraction, which comprises:

a) gasifying means including a first end and a second end;

b) a feeding zone at the first end of the gasifying means;

c) a solid fuels feeding means, placed at the feeding zone of the gasifying means, to control feeding of solid fuels;

d) a gasifying zone coupled to the feeding zone wherein partial combustion takes place;

e) air feeding means connected to the gasifying zone for feeding air for the partial combustion of solid fuels, including a hot air input from a suitable source at the gasifying zone in order to control the temperature thereof;

f) retaining means in the gasifying zone for controlling permeability and residence time of the solid fuels in the gasifying zone, including cooling means located inside the retaining means to avoid melting of the solid fuel on the retaining means;

g) driving means for the retaining means adapted to completely put or withdrawn said retaining means for discharging the coal fraction and the non-coal fraction after complete separation of the gaseous fraction of the solid fuels and for continuously discharging solids and avoiding formation of agglomerates in the gasifying means;

h) a gas exhaust into which the gaseous fraction is discharged from the gasifying zone for further use;

i) a discharging zone coupled to the gasifying zone; and

j) discharging means at the discharging zone which receives the coal fraction and the non-coal fraction from the gasifying zone and which discharges the coal fraction and the non-coal fraction from the discharging zone;

wherein the solid fuel coal, solid and gaseous fraction follow a path inside the apparatus through the feeding zone, the gasifying zone and discharging zone, and wherein the air feeding means, provide an air current that is co-current with the solid fuels fractions path inside the apparatus.

58. An apparatus for fractionating whole tires having tire beads of steel wire into a gaseous fraction, a coal fraction, and a non-coal fraction, which comprises:

a) gasifying means including a first end and a second end;

b) a feeding zone at the first end of the gasifying means;

c) a whole tire feeding means, placed at the feeding zone of the gasifying means to control the feeding of the whole tires;

d) a gasifying zone coupled to the feeding zone wherein partial combustion of the whole tires takes place;

e) air feeding means connected to the gasifying zone for feeding air for the partial combustion of the whole tires, including a hot air input from a suitable source at the gasifying zone in order to control the temperature thereof;

f) retaining means in the gasifying zone for controlling permeability and residence time of the whole tires in the gasifying zone, including cooling means located inside the retaining means to avoid melting of the whole tires on the retaining means;

g) driving means for the retaining means adapted to completely put or withdrawn said retaining means for discharging the coal fraction and the non-coal fraction after complete separation of the gaseous fraction of the whole tires and for continuously discharging steel wire and other solids and avoiding formation of agglomerates in the gasifying means;

h) a gas exhaust into which the gaseous fraction is discharged from the gasifying zone for further use;

i) a discharging zone coupled to the gasifying zone; and

j) discharging means at the discharging zone which receives the coal fraction and the non-coal fraction from the gasifying zone and which discharges the coal fraction and the non-coal fraction from the discharging zone;

wherein the whole tire coal, solid and gaseous fraction follows a path inside the apparatus through the feeding zone, the gasifying zone and discharging zone, and wherein the air feeding means, provide a hot air current that is co-current with the solid fuels fractions path inside the apparatus.

59. The apparatus according to claim 57, wherein the solid fuels feeding means comprise a feeding valve including driving means to open and close said feeding valve.

60. The apparatus according to claim 57, wherein the solid fuels feeding means comprise a plurality of gates in which solid fuels are fed.

61. The apparatus according to claim 57, wherein the retaining means comprise a plurality of grills.

62. The apparatus according to claim 57, wherein the cooling means of the retaining means include internal pipes inside the retaining means into which cool water is circulated by means of a pump.

63. The apparatus according to claim 57, wherein the cooling means of the retaining means include internal pipes inside the retaining means into which cool air is circulated by means of a pump.

64. The apparatus according to claim 57, wherein the driving means for the retaining means comprise hydraulic motors alternately introduce or withdraw said retaining means.

65. The apparatus according to claim 57, wherein the solid fuels feeding means feeds the solid fuel to the gasifying zone, by a hydraulic piston and cylinder assembly.

66. The apparatus according to claim 57, wherein the discharging means discharge the coal fraction and the non-coal fraction from the gasifying zone, by a hydraulic piston and cylinder assembly.

67. The apparatus according to claim 57, wherein the discharging means discharges the coal fraction and the non-coal fraction from the discharging zone to outside of the apparatus, by gravity.

68. The apparatus according to claim 57, wherein the discharging means discharges the coal fraction and the non-coal fraction from the discharging zone to outside of the apparatus, by a hydraulic piston and cylinder assembly.

69. The apparatus according to claim 57, wherein the discharging valves include driving means which open and close said discharging means in order to discharge the coal fraction and the non-coal fraction from the apparatus.

70. The apparatus according to claim 57, wherein the air feeding means include a hot air input which takes hot air from a tertiary air duct of a cement kiln, and the gas exhaust means discharges the gaseous fraction to a pre-calcinator or calcinator section of the cement kiln to substitute primary fuel, and the coal fraction to a kiln input to substitute primary fuel and the non-coal fraction is integrated to a cement clinker.

71. The apparatus according to claim 57, wherein the discharging means discharges the non-coal fraction to a feeding conveyor belt of a kiln for producing cement.

72. The apparatus according to claim 57, wherein the discharging means discharges the coal fraction to a main burner of a kiln for producing cement.

73. The apparatus according to claim 57, wherein the air feeding means include a hot air input which takes hot air from a cement clinker cooler and the discharging means discharge the non-coal fraction outside of the gasifying means, to containers for an application to a recuperator of a cement kiln having no pre-calcinator.

74. The apparatus according to claim 57, wherein the discharging means discharge the coal fraction into a main burner of a cement kiln having no pre-calcinator.

75. The apparatus according to claim 58, wherein the gasifying means comprises a vertical column.

76. The apparatus according to claim 58, wherein the whole tire feeding means valve comprise a feeding valve including driving means to open and close said feeding valves.

77. The apparatus according to claim 58, wherein the whole tire feeding means comprises a plurality of gates in which whole tires are fed.

78. The apparatus according to claim 58, wherein the retaining means comprise a plurality of grills.

79. The apparatus according to claim 58, wherein the retaining means comprising a mesh and wherein the cooling means of the retaining means include internal pipes inside said mesh, into which cool water is circulated by means of a pump.

80. The apparatus according to claim 58, wherein the driving means for the retaining means comprise hydraulic motors to alternately introduce or withdraw said mesh.

81. The apparatus according to claim 58, wherein the discharging means comprise a plurality of gates.

82. The apparatus according to claim 58, wherein the discharging means include driving means.

83. The apparatus according to claim 82, wherein the driving means of the discharging means comprises hydraulic motors which raise and lower said discharging means.

84. The apparatus according to claim 58, wherein whole tire feeding means feed the whole tires to the gasifying zone by gravity.

85. The apparatus according to claim 58, wherein the whole tire feeding means feeds the whole tires to the gasifying zone by a hydraulic piston and cylinder assembly.

86. The apparatus according to claim 58, wherein the discharging means discharge the coal fraction and the non-coal fraction from the gasifying zone to the discharging zone by gravity.

87. The apparatus according to claim 58, wherein the discharging means discharges the coal fraction and the non-coal fraction from the gasifying zone by a hydraulic piston and cylinder assembly.

88. The apparatus according to claim 58, wherein the discharging means discharges the coal fraction and the non-coal fraction from the discharging zone to outside of the apparatus by gravity.

89. The apparatus according to claim 58, wherein the discharging means discharges the coal fraction and the non-coal fraction from the discharging zone to outside of the apparatus by a hydraulic piston and cylinder assembly.

90. The apparatus according to claim 58, wherein the discharging valves include driving means which open and close the discharging means in order to discharge the coal fraction and the non-coal fraction from the apparatus.

91. The apparatus according to claim 58, wherein the hot air input of the air feeding means takes hot air from a tertiary air duct of a cement kiln, the gaseous fraction is discharged through the gas exhaust to a pre-calcinator or calcinator section of the cement kiln to substitute primary fuel, and the coal and non-coal fractions are discharged through the discharging zone by the discharging means to a kiln input to substitute the primary fuel and integrated into a cement clinker respectively.

92. The apparatus according to claim 58, wherein the discharging means discharges the non-coal fraction to a feeding conveyor belt of a cement kiln.

93. The apparatus according to claim 58, wherein the discharging means discharges the coal fraction to a main burner of a cement kiln.

94. The apparatus according to claim 58, wherein the air feeding means includes a hot air input which takes hot air from a cement clinker cooler and the discharging means discharge the non-coal fraction outside of the gasifying means, to containers for an application to a recuperator of a cement kiln having no pre-calcinator.

95. The apparatus according to claim 58, wherein the discharging means discharges the coal fraction into a main burner of a cement kiln having no pre-calcinator for producing cement.

96. The apparatus according to claim 58, wherein the apparatus operates at a temperature of between about 900° C. and about 1150° C.