EP1026938A1

EP1026938A1 - Apparatus and method for introducing compressible fuel into a gasifier

Info

Publication number: EP1026938A1
Application number: EP99901288A
Authority: EP
Inventors: Titus Hilliard; Wesley P. Hilliard
Original assignee: Emery Recycling Corp
Current assignee: Emery Recycling Corp
Priority date: 1998-01-06
Filing date: 1999-01-05
Publication date: 2000-08-16
Also published as: ZA9946B; AU2102299A; WO1999034662A1

Abstract

An apparatus and method for introducing a compressible fuel, such as rubber, plastic, wood, paper products, and similar materials, into a gasifier is disclosed. The apparatus includes one or more stages of compression. One or more preheaters (96) are provided to soften or melt the fuel material during start-up of the gasifier. In operation, heat from the gasifier softens or melts the fuel material. One or more holes (42) located adjacent the exit end of the feed tube (16) allow the softened fuel material to exit the apparatus and enter the gasifier. In one embodiment, a 'neck' region in combination with the compression forces the softened fuel material to exit the apparatus and enter the gasifier. In another embodiment, a gate temporarily blocks the exit end of the feed tube forcing the softened compressed fuel through the holes. This allows for separation of non-combustibles, such as wires used in reinforced tires, from the fuel material.

Description

APPARATUS AND METHOD FOR INTRODUCING COMPRESSIBLE FUEL INTO A GASIFIER

Field of the Invention The present invention relates to an apparatus for introducing various fuel materials into a gasifier, including pressurized gasifiers.

Technology Background A fuel gasifier or similar combustion reactor must include a mechanism for introducing the fuel material into the gasifier. If the gasifier operates at ambient pressure, then the fuel material can simply be fed or dropped into the gasifier with simple conveyor equipment. Often the gasifier' s interior is pressurized, making it more complicated to introduce fuel into the pressurized interior. Augers are commonly used to introduce fuel material to pressurized gasifiers. A series of gates can also be used to introduce fuel into a pressurized gasifier.

Augers and gates are suitable for fuel materials which are dry and homogeneous, such as coal and wood. But in practice, gasifiers are often used with non-homogeneous fuel materials, such as municipal or other waste materials. Because of large variations in the composition and moisture content of municipal waste, complicated sorting, drying, and shredding operations are typically required to successfully use the waste fuel material with augers and gates. Used tires are commonly shredded when used in gasifiers, but shredding cuts and exposes wires which has the negative effect of inhibiting the handling, flow and processing of shredded tires. Used tires are particularly difficult to use in gasifiers because they possess both combustible and noncombustible parts. The noncombustible reinforcing wires used in tires are difficult to separate from the combustible rubber material. If the reinforcing wires are not separated prior to burning or gasifying the tires, the wires form a major portion of the ash which must be constantly removed. Wires can also potentially damage the interior of the gasifier device. It would be a significant advancement in the art to provide an apparatus for introducing fuel materials into a gasifier which does not require the fuel to be dried or shredded.

It would be a further advancement in the art to provide an apparatus for introducing compressible fuel materials, such as rubber, plastic, wood, and paper, into a pressurized gasifier.

It would be yet another advancement in the art to provide an apparatus for introducing used tires into a gasifier which separates the reinforcing wires and which does not require prior shredding of the tire.

Such apparatus for introducing fuel materials into a gasification apparatus are disclosed and claimed herein.

Summary of the Invention The present invention provides an apparatus for introducing a compressible fuel, such as rubber, plastic, wood, paper products, and similar materials, into a gasifier. As used herein the term gasifier is intended to include fuel gasifiers, furnaces, and other combustion reactors. The apparatus compresses the fuel material using one or more stages of compression. In a typical single-stage compression system, the fuel material is introduced directly into the feed tube and compressed. In a typical two-stage compression system, preliminary compression occurs within a preliminary compression tube and final compression within a feed tube. In a three- and four-stage compression system, the fuel material undergoes some compression before entering the preliminary compression tube.

In operation, heat from the gasifier and the high pressure compression softens or melts the fuel material. One or more holes located adjacent the exit end of the feed tube allow the softened fuel material to exit the apparatus and enter the gasifier. The portion of the feed tube containing such holes is preferably located within the gasifier. In some embodiments, the feed tube exit end is located within the gasifier. The apparatus preferably includes a preheater on the feed tube to assist in "start-up" of the apparatus for introducing compressible fuel into a gasifier. It has been observed that if the gasifier is shut down with softened or melted fuel material remaining in the feed tube, that the fuel material can solidify upon cooling and plug the feed tube, rendering it very difficult or impossible to restart the flow of fuel through the feed tube. Preheaters can heat the feed tube sufficiently to soften the fuel and permit its continued flow into the gasifier. In one embodiment, a "neck" region in combination with the compression causes the softened fuel to pass through the holes. Non-melted or non-combustible materials pass through "neck" region for future disposal. This allows for separation of non- combustibles, such as wires used in reinforced tires. In another embodiment, a gate temporarily blocks the exit end of the feed tube forcing the compressible, combustible fuel material through the holes. The gate is periodically opened to allow the noncompressible, noncombustible material to be expelled from the feed tube. The preliminary compression tube has a ram end and an exit end. The preliminary compression tube is sized to accommodate a compression piston coupled to a compression ram for moving the compression piston through the preliminary compression tube. In one embodiment, at least one side wall of the preliminary compression tube is a hinged gate to provide interior access to the compression tube. The gate is coupled to a gate ram for opening and closing the gate. In operation, compressible fuel material is introduced into the preliminary compression tube through the gate, and the compression piston compresses and moves the fuel towards the exit end and into the feed tube. In another preferred embodiment, additional compression stages are provided to compress the fuel into a size capable of being loaded in the preliminary compression tube. For instance, when the fuel is used tires, it is desirable to have a fuel inlet region sized to accommodate various sized tires, particularly of different tire widths. The apparatus includes a movable side wall for compressing wide tires to a standard width size and a fuel feed piston for moving the tires to the preliminary compression tube which, in turn, compresses and moves the fuel into the feed tube.

The feed tube also has a ram end and an exit end. The feed tube is sized to accommodate a feed piston coupled to a feed ram for moving the feed piston through the feed tube. The feed tube is preferably oriented transverse to the compression tube such that the exit end of the compression tube opens into ram end of the feed tube. This allows compressed fuel from the compression tube to enter the feed tube and for the feed piston to further compress and move the fuel towards through the feed tube towards the exit end.

The apparatus of the present invention is particularly useful for introducing used tires, plastics, wood, paper products, and similar waste materials into a gasifier.

Brief Description of the Drawings

Figure 1 is a perspective view of an apparatus for introducing compressible fuel materials into a gasification apparatus within the scope of the present invention.

Figure 2 is a cross sectional view of the apparatus shown in Figure 1.

Figure 3 is a cross sectional view of the apparatus shown in Figure 1 showing one method of introducing used tires into the apparatus.

Figure 4 is a cross sectional view of the apparatus shown in Figure 1 showing a used tire within the preliminary compression tube.

Figure 5 is a cross sectional view of the apparatus shown in Figure 1 showing a used tire partially compressed and introduced into the feed tube. Figure 6 is a cross sectional view of the apparatus shown in Figure 1 showing a used tire further compressed within the feed tube.

Figure 7 is a cross sectional view of the apparatus shown in Figure 1 showing a plurality of used tires compressed within the feed tube causing fuel material to be introduced within a gasifier.

Figure 8 is a cross sectional view of a neck region having a narrowed cross-section and a plurality of holes to allow fuel material to be introduced within a gasifier. Figure 9 is a cross sectional view of a single-stage compression apparatus within the scope of the present invention showing fuel material introduced directly into the feed tube. Figure 10 is a cross sectional view of the apparatus shown in Figure 9 showing fuel material compressed within the feed tube.

Figure 11 is a cross sectional view of the apparatus shown in Figure 9 showing additional fuel material introduced into the feed tube.

Figure 12 is a cross sectional view of an gate for temporarily blocking the exit end of the feed tube and for forcing the compressible, combustible fuel material through the holes into the gasifier.

Figure 13 is a perspective view of another apparatus for introducing compressible fuel materials into a gasification apparatus within the scope of the present invention.

Figure 14 is a cross sectional view of the apparatus shown in Figure 13 showing one method of introducing used tires into the apparatus.

Figure 15A is a top view of the apparatus shown in Figure 13 showing an extra-wide tire within the fuel inlet region.

Figure 15B is a top view of the apparatus shown in Figure 15A showing side wall compression of the extra-wide tire within the fuel inlet region.

Figure 16 is a cross sectional view of the apparatus shown in Figure 13 showing a used tire within the preliminary compression tube. Figure 17 is a cross sectional view of the apparatus shown in Figure 13 showing a used tire compressed and introduced into the feed tube.

Figure 18 is a cross sectional view of the apparatus shown in Figure 13 showing a used tire further compressed within the feed tube as it is introduced into a gasifier device.

Detailed Description of the Invention The present invention is directed to an apparatus for introducing a compressible fuel, such as rubber, plastic, wood, paper products, and similar materials, into a gasifier. Reference is made to the drawings wherein like parts are designated with like numerals throughout. Referring to Figures 1 and 2 , one currently preferred apparatus for introducing fuel into a gasifier is illustrated generally as 10. Fuel introducer apparatus 10 includes a fuel inlet region 12 wherein compressible fuel is introduced into the apparatus, a preliminary compression tube 14 and a feed tube 16.

In one embodiment within the scope of the present invention, illustrated in Figures 2-7, at least one side wall of the preliminary compression tube 14 is a hinged gate 18 to provide interior access to the preliminary compression tube 14. The gate 18 is coupled to a gate ram 20 and gate hinge 22 such that operation of the gate ram 20 opens and closes the gate 18. Figures 3 and 4 illustrate the gate being opened and closed to allow fuel 24 (illustrated as used tires) into the preliminary compression tube 14.

In another preferred embodiment within the scope of the present invention, illustrated in Figures 13-18, one side wall of the preliminary compression tube functions as a fuel inlet piston 90 for pushing fuel 24 into the preliminary compression tube 14. The fuel inlet region 12 includes a movable side wall 92 for compressing tires having various widths to a standard width. This is particularly useful for light truck tires which often have widths up to 12 inches. The fuel inlet piston 90 compresses and pushes the fuel 24 into the preliminary compression tube 14. As shown in Figures 14-16, additional compression stages are provided to compress the fuel 24 into a size capable of being loaded in the preliminary compression tube 14. The fuel inlet piston 90 is coupled to one or more fuel inlet rams 94. As shown best in Figures 13, 15A, and 15B, the movable side wall 92 is coupled to one or more wall rams 96 which move the wall 92 to compress the fuel 24, such as wide tires. The preliminary compression tube 14 has a ram end 26 and an exit end 28. The preliminary compression tube 14 is sized to accommodate a preliminary compression piston 30 coupled to a preliminary compression ram 32 for moving the preliminary compression piston 30 through the preliminary compression tube 16. As shown best in Figures 4-5 and 16-17, extension of the one or more rams 32 moves the piston 30 from the ram end 26 towards the exit end 28 of the preliminary compression tube 14. Fuel 24 located within the preliminary compression tube 14 is compressed and moved to the exit end 28 and into the feed tube 16.

The feed tube 16 also has a ram end 34 and an exit end 36. As shown in the Figures, the feed tube 16 is preferably oriented approximately transversely to the preliminary compression tube

14 such that the exit end 28 of the preliminary compression tube 14 opens into the feed tube 16 at a location adjacent the ram end 34 of the feed tube. In this manner, compressed fuel 24 enters the feed tube 16 adjacent the ram end 34 of the feed tube 16.

The feed tube 16 is sized to accommodate a feed piston 38 coupled to a feed ram 40 for moving the feed piston 38 through the feed tube 16. As shown best in Figures 5-6 and 17-18, extension of the ram 40 moves the piston 38 from the ram end 34 towards the exit end 36 of the feed tube 16. This allows compressed fuel 24 to be moved through the feed tube 16 towards the exit end 36. The feed tube 16 preferably includes one or more holes 42 to allow the fuel material 24 to exit the apparatus 10 and enter the gasifier. The holes 42 can vary in size depending on the type of fuel material used, but will typically range in size from inch to inch, with a size of about % inch being preferred for used tires. It is within the scope of the present invention for the feed tube 16 to exit directly into the gasifier. A gasifier connection flange 95 is preferably provided to facilitate connecting the apparatus 10 to a gasifier.

The portion of the feed tube 16 containing holes 42 is preferably located within the gasifier. A representation of a typical gasifier wall 46 is shown in Figures 7 and 18. Heat from the gasifier at least partially melts the fuel material 24. Referring to Figures 7 and 18, heat-softened fuel material combined with the repeated introduction and compression of fuel 24 causes the fuel material 24 to merge into a single compressed fuel mass 44. Where the gasifier operates at high pressure, the fuel mass 44 provides an effective pressure seal between the gasifier interior and the fuel material being introduced to the gasifier.

The feed tube 16 preferably includes a preheater to assist in "start-up" of the apparatus for introducing compressible fuel into a gasifier. It has been observed that if the gasifier is shut down with softened or melted fuel mass 44 remaining in the feed tube 16, that the fuel mass 44 can solidify upon cooling and plug the feed tube 16, rendering it very difficult or impossible to restart the flow of fuel through the feed tube 16. Preheaters can heat the feed tube 16 sufficiently to soften the fuel mass 44 and permit its continued flow into the gasifier. The preheater preferably provide sufficient heat to raise the temperature of the fuel mass to about 160°C, as measured by temperature sensors (not shown) . The gasifier provides sufficient heat during operation to maintain the temperature within the feed tube between 160°C and 180°C. Thus, the preheaters are preferably used during start-up of the gasifier. It is presently preferred to use electric heating elements 96, shown in Figures 14-18, to preheat the feed tube 16.

Persons skilled in the art will appreciate that gas burning preheaters or similar devices can also be used. It is presently preferred to mount the heating elements 96 on the top and bottom surfaces of the feed tube 16. The heating elements 96 are preferably mounted in pairs, with each heating element 96 requiring about 3.7 kW at 220 volts, making the total wattage requirement of about 15 kW. The heating elements are connected to a source of electric power (not shown) . It has been found that mounting the heating elements 96 on the outside surface of the feed tube 16 facilitates replacement of damaged or inoperative heating elements 96 when necessary. Other heating element configurations are within the skill in the art, including gas fired heating elements.

If the temperature within the feed tube 16 exceeds a desired operating temperature range, a water spray head 98, shown in Figure 18, is preferably used to cool the feed tube 16. The water spray head 98 is connected to a source of water (not shown) . The temperature can be controlled by providing short, intermittent water sprays until the desired temperature is obtained.

One skilled in the art will appreciate that the application of high pressures to a compressible fuel material will increase the temperature of the fuel and may decrease the need for external heating. Thus, direct heating of the fuel material by the gasifier may not be necessary in some applications. In one embodiment within the scope of the present invention, illustrated in Figure 8, the feed tube 16 includes a neck region 48 having a narrowed cross section near the holes 42. The neck region 48 combined with the holes 42 forces the compressible fuel 44 out of the holes 42 while retaining noncompressible material 49 within the feed tube 16 for subsequent discharge from the feed tube 16. In another embodiment shown in Figure 12, a sheer gate 56 temporarily blocks the exit end 36 of the feed tube 16 forcing the compressible, combustible fuel material through the holes 42. The sheer gate 56 is connected to a sheer gate ram 58. The sheer gate 56 is periodically opened to allow the noncom- pressible, noncombustible material to be expelled from the feed tube 16. In the embodiment illustrated in Figure 12, the sheer gate 56 slides within a spacer block 60 which is sandwiched between a flange 62 and an outer block 64. The spacer block 60, flange 62, and outer block 64 are preferably joined together using conventional connectors, such as bolts and screws.

Referring to Figures 9-11, a single-stage apparatus 70 for introducing a fuel material into a gasifier is shown. Fuel material 72 is introduced directly into the feed tube 74 via fuel opening 76. The feed tube 74 is substantially the same as the feed tube 16. Feed tube 74 also has a ram end 78 and an exit end 80. As shown in Figures 9-11, the fuel material 72 enters the feed tube 74 adjacent the ram end 78 of the feed tube 74.

The feed tube 74 is sized to accommodate a feed piston 82 coupled to a feed ram 84 for moving the feed piston 82 through the feed tube 74. As shown best in Figure 10, extension of the ram 84 moves the piston 82 from the ram end 78 towards the exit end 80 of the feed tube 74. This allows compressed fuel material to be moved through the feed tube 74 towards the exit end 80. The feed tube 74 preferably includes one or more holes 42 to allow the fuel material 72 to exit the apparatus 70 and enter the gasifier. As explained above, the holes 42 can vary in size depending on the type of fuel material used, but will typically range in size from inch to % inch. The feed piston 82 is preferably elongated such that its longitudinal sides 86 cover the fuel opening 76 during extension of the ram 84, as shown in Figure 10. The corner edge 88 at the intersection of the opening 76 and the feed tube 74 is preferably reinforced so that it is capable of sheering or cutting the fuel material 72 as the feed piston 82 pushes fuel against the edge 88.

The apparatus for introducing fuel is preferably constructed of steel or other suitable material capable of withstanding the high pressures generated within the preliminary compression tube and the feed tube. One inch steel plate is suitable for most applications. Operating pressures can range up to 60 tons, but are typically about 3200 psi in normal operation. Those portions of the apparatus which are located within the gasifier should also be constructed of a material capable of withstanding the operating temperatures within the gasifier. Suitable reinforcement is also included on the apparatus. For instance, the apparatus illustrated in Figures 1-8 includes reinforcing members 50 positioned around the feed tube.

It will be appreciated that the present invention provides an apparatus for introducing fuel materials into a gasifier which does not require the fuel to be dried or shredded. The present invention further provides an apparatus for introducing compressible fuel materials, such as rubber, plastic, wood, and paper products, into a pressurized gasifier. The present invention can also be used to introduce waste or other hazardous materials into a gasifier by combining the waste with an innocuous compressible carrier or substrate. The carrier or substrate can also include substances which neutralize the hazardous material.

Claims

CLAIMS :

1. An apparatus for introducing a compressible fuel into a gasifier comprising: a fuel inlet region for receiving compressible fuel having a fuel inlet end and an exit end, wherein the fuel inlet region further comprises a fuel feed ram for moving fuel from the fuel inlet end towards the exit end; a preliminary compression tube having a ram end and an exit end, wherein the compression tube is sized to accommodate a compression piston coupled to a compression ram for moving the compression piston through the compression tube, such that in operation, the compression piston compresses and moves the fuel towards the exit end; a feed tube having a ram end and an exit end, wherein the feed tube is oriented approximately transversely to the compression tube such that the exit end of the compression tube opens into the feed tube at a location adjacent the ram end of the feed tube such that compressed fuel from the compression tube enters the feed tube adjacent the ram end of the feed tube, wherein the feed tube is sized to accommodate a feed piston coupled to a feed ram for moving the feed piston through the feed tube such that the feed piston further compresses and moves the fuel towards the exit end of the feed tube; and one or more preheaters located adjacent the feed tube to heat the feed tube.

2. An apparatus as defined in claim 1, wherein the fuel inlet region further comprises a side wall compression ram and piston for compressing the fuel within the fuel inlet region.

3. An apparatus as defined in claim 1, wherein a side wall of the compression tube comprises a hinged gate which is coupled to the fuel feed ram for opening and closing the gate to provide interior access to the compression tube.

4. An apparatus as defined in claim 1, wherein the one or more preheaters is capable of heating the feed tube to a temperature in the range from about 160┬░C to about 180┬░C.

5. An apparatus as defined in claim 1, wherein the feed tube further comprises a neck region having a narrowed cross- section and wherein a plurality of holes are located at the neck region.

6. An apparatus as defined in claim 5, wherein the neck region combined with the plurality of holes forces the compressible fuel out of the holes while retaining noncompressible materials within the feed tube for subsequent discharge at the exit end of the feed tube.

7. An apparatus as defined in claim 1, wherein the feed tube further comprises one or more holes located adjacent the exit end of the feed tube and a movable sheer gate for temporarily blocking the exit end of the feed tube.

8. An apparatus as defined in claim 7, wherein fuel compressed against the sheer gate forces the fuel out of the holes while retaining noncompressible materials within the feed tube for subsequent discharge at the exit end of the feed tube.

9. An apparatus as defined in claim 1, wherein heat from the gasifier partially melts the fuel material to facilitate exit of the fuel from the feed tube.

10. An apparatus as defined in claim 1, wherein the compressible fuel is selected from rubber and plastic.

11. An apparatus as defined in claim 10, wherein the compressible fuel is used tires.

12. An apparatus as defined in claim 1, wherein the compressible fuel is selected from wood and paper products.

13. An apparatus for introducing used tires into a gasifier comprising: a fuel inlet region for receiving compressible used tires having a fuel inlet end and an exit end, wherein the fuel inlet region further comprises a side wall compression ram and a piston for compressing wide used tires and a fuel feed ram coupled to said piston for moving said tires from the fuel inlet end towards the exit end; a preliminary compression tube having a ram end and an exit end, wherein the compression tube is sized to accommodate a compression piston coupled to a compression ram for moving the compression piston through the compression tube, such that in operation the compression piston compresses and moves the tires towards the exit end; a feed tube having a ram end and an exit end, wherein the feed tube is oriented approximately transversely to the compression tube such that the exit end of the compression tube opens into the feed tube at a location adjacent the ram end of the feed tube such that compressed tires from the compression tube enter the feed tube adjacent the ram end of the feed tube, wherein the feed tube is sized to accommodate a feed piston coupled to a feed ram for moving the feed piston through the feed tube such that the feed piston further compresses and moves the tires towards the exit end of the feed tube, wherein a portion of the feed tube is located within the gasifier; one or more preheaters located adjacent the feed tube to heat the feed tube; and a neck region located within the gasifier adjacent the exit end of the feed tube and having a narrowed cross- section, wherein heat from the gasifier partially melts the fuel material, wherein the neck region contains a plurality of holes such that the neck region combined with the plurality of holes and the movement of the compressed tires through the feed tube forces the compressible fuel through the holes into the gasifier while retaining noncompressible materials within the feed tube for subsequent discharge at the exit end of the feed tube.

14. An apparatus for introducing fuel material into a gasifier comprising: a feed tube having a ram end and an exit end, wherein the feed tube defines a fuel opening adjacent the ram end through which fuel material is introduced into the feed tube, wherein the feed tube is sized to accommodate a feed piston coupled to a feed ram for moving the feed piston through the feed tube such that the feed piston compresses and moves the fuel material towards the exit end of the feed tube; one or more preheaters located adjacent the feed tube to heat the feed tube to a temperature in the range from about 160┬░C to about 180┬░C.

15. An apparatus as defined in claim 14, further comprising one or more holes located adjacent the exit end of the feed tube and means for blocking or partially blocking the exit end of the feed tube to cause compressed fuel to exit the apparatus through the one or more holes.

16. An apparatus as defined in claim 15, wherein the means for blocking or partially blocking the exit end of the feed tube includes a neck region having a narrowed cross-section and wherein the plurality of holes are located at the neck region.

17. An apparatus as defined in claim 15, wherein the means for blocking or partially blocking the exit end of the feed tube includes a movable sheer gate for temporarily blocking the exit end of the feed tube.

18. An apparatus as defined in claim 14, wherein the feed tube exit end is located within the gasifier.

19. An apparatus as defined in claim 18, wherein heat from the gasifier partially melts the fuel material to facilitate exit of the fuel from the feed tube.

20. An apparatus as defined in claim 14, wherein the compressible fuel is selected from rubber and plastic.

21. An apparatus as defined in claim 20, wherein the compressible fuel is used tires.

22. An apparatus as defined in claim 14, wherein the compressible fuel is selected from wood and paper products.

23. A method for introducing a compressible fuel into a gasifier comprising the steps: (a) introducing compressible fuel into a preliminary compression tube;

(b) compressing the compressible fuel with the compression piston such that the fuel moves through the compression tube towards the exit end of the compression tube;

(c) introducing the compressed fuel into a feed tube having a ram end and an exit end, wherein the feed tube is oriented approximately transversely to the compression tube such that the exit end of the compression tube opens into the feed tube at a location adjacent the ram end of the feed tube to allow compressed fuel from the compression tube to enter the feed tube adjacent the ram end of the feed tube, wherein the feed tube is sized to accommodate a feed piston coupled to a feed ram, the feed tube further comprising one or more holes located adjacent the exit end of the feed tube to allow the fuel material to exit the feed tube and enter the gasifier; and

(d) heating the feed tube to soften or melt the fuel material within the feed tube; and

(e) moving the feed piston through the feed tube to further compress and move the fuel towards the exit end of the feed tube and cause the fuel to exit the feed tube.

24. A method as defined in claim 23, further comprising the step of opening a gate to the preliminary compression tube, wherein the preliminary compression tube has a ram end and an exit end, wherein the preliminary compression tube is sized to accommodate a compression piston coupled to a compression ram for moving the compression piston through the compression tube, wherein the gate at least partially comprises one side wall of the compression tube.

25. A method as defined in claim 23, wherein the feed tube further comprises a neck region having a narrowed cross-section and a plurality of holes.

26. A method as defined in claim 24, 25, wherein the neck region is located in the gasifier and wherein heat from the gasifier partially melts the fuel material to facilitate exit of the fuel through the holes.

27. A method as defined in claim 23, wherein the compressible fuel is selected from rubber and plastic.

28. A method as defined in claim 27, wherein the compressible fuel is used tires.

29. A method as defined in claim 23, wherein the compressible fuel is selected from wood and paper products.

30. A method for introducing a fuel material into a gasifier comprising the steps:

(a) introducing the fuel material into a feed tube having a ram end and an exit end, wherein the feed tube is sized to accommodate a feed piston coupled to a feed ram, the feed tube further comprising one or more holes located adjacent the exit end of the feed tube to allow the fuel material to exit the feed tube and enter the gasifier;

(b) heating the feed tube with one or more preheaters to at least partially soften or melt the fuel material; and (c) moving the feed piston through the feed tube to compress and move the fuel towards the exit end of the feed tube.

31. A method as defined in claim 30, wherein the step of heating the feed tube occurs at start-up of the gasifier.

32. A method as defined in claim 30, further comprising the step of at least partially blocking the exit end of the feed tube to cause the fuel to exit the feed tube into the gasifier through the one or more holes.

33. A method as defined in claim 30, wherein the compressible fuel is selected from rubber and plastic.

34. A method as defined in claim 33, wherein the compressible fuel is used tires.

35. A method as defined in claim 30, wherein the compressible fuel is selected from wood and paper products.