Biofuel Gasification Reactor

Abstract

A biofuel gasification reactor for producing gases that are combustible in an internal combustion engine. The reactor includes a vessel with a loading port and cover, sized to receive biofuel of at least eight by twenty inches. A storage zone provides biofuel via gravity feed only to a plasma zone that oxidizes the biofuel into char and precursor gases. Air nozzles provide air to the plasma zone from a helical air preheater. A char zone receives the precursor gases and char. The precursor gases are substantially converted to effluent gases of hydrogen and carbon monoxide. A grating below the char zone holds the char until it is oxidized to ash. The grating covers the entire bottom of the char zone. The grating is disposed in a substantially fixed and immovable configuration during the operation of the reactor.

Description

FIELD

This invention relates to the field of alternative energy sources. More particularly, this invention relates to a biofuel gasification reactor.

INTRODUCTION

Facilities in remote areas often require electricity, either for the convenience and comfort of the facility personnel, or to run some of the equipment installed at the facility. Various methods are used to provide this electricity, including installing lengthy runs of power transmission lines, solar cells, batteries, and generators that run on a variety of different petroleum products.

Unfortunately, each of these power sources tends to suffer from a variety of different limitations or problems. For example, installing power lines can provide an adequate supply of electricity at relatively low on-going costs, but tends to have enormous up-front costs—costs that cannot be justified if the run is too lengthy, or the facility will not be operational long enough. Solar cells and batteries tend to only provide a limited amount of energy. Gasoline, diesel fuel, or other petroleum distillates must typically be trucked-in to the facility site to supply a generator, which complicates the supply logistics for the facility, and can also be quite expensive.

What is needed, therefore, is a system that reduces problems such as those described above, at least in part.

SUMMARY

The above and other needs are met by a biofuel gasification reactor for producing effluent gases that are combustible in an internal combustion engine. The reactor includes an elongate vessel disposed in an upright orientation. A biofuel loading port is at the top of the vessel, has a cover, and is sized to receive biofuel of at least about eight inches in diameter and twenty inches in length. A biofuel storage zone is disposed below the loading port, and stores and provides the biofuel to lower zones within the reactor via gravity feed only.

A plasma zone is below the storage zone, and oxidizes the biofuel into char and precursor gases containing at least carbon dioxide and water vapor. The plasma zone has a tapered configuration that is wider at the top and narrower at the bottom. Air nozzles are radially disposed through a circumference of the vessel at the plasma zone for providing air to the plasma zone. A helical air preheater is disposed outside the vessel and wrapped around the circumference of the vessel at the plasma zone for receiving air from an ambient environment and providing the air to the nozzles. A reduction zone is below the plasma zone for receiving the precursor gases and char from the plasma zone, having a diameter that is less than the diameter of the vessel.

A char zone is below the reduction zone and receives the precursor gases and char from the reduction zone. The char zone has a tapered configuration that is wider at the bottom and narrower at the top. The precursor gases are substantially converted to effluent gases of hydrogen and carbon monoxide within at least one of the reduction zone and the char zone.

A grating is below the char zone and holds the char until it is oxidized to ash, then permitting the ash to fall through. The grating is disposed in a substantially fixed and immovable configuration during the operation of the reactor. The grating passes substantially all of the effluent gases to an ash cone that is beneath and partially surrounds the vessel, and receives the ash through the grating. An effluent gas outlet port in the ash cone above the bottom of the vessel provides the effluent gases to an internal combustion engine.

In various embodiments, the plasma zone, reduction zone, and char zone are all formed of refractory brick inside the reactor vessel. In some embodiments the reactor vessel is formed of steel. In some embodiments the grating is formed of steel. In some embodiments the reduction zone has a diameter of about 27 inches. In some embodiments the vessel has a diameter of about 108 inches. In some embodiments the vessel has a length of about 200 inches. In some embodiments the plasma zone and the reduction zone each have a height of about 28 inches. In some embodiments the grating is about 24 inches square. In some embodiments the preheater makes about three complete revolutions around the vessel.

According to another aspect of the invention there is described a biofuel gasification system that includes the reactor described above, which produces effluent gases. A cyclone receives the effluent gases from the reactor, and dries, cools, and purifies the effluent gases at least in part. A selectively by-passable blower draws the effluent gases from the cyclone during a startup phase of the system. A condenser selectively receives the effluent gases from the blower during at least a portion of the startup phase of the system, and dries, cools, and purifies the effluent gases at least in part. A first flare receives the effluent gases from the condenser and indicates the presence of the effluent gases by igniting them. A cooling tower selectively receives the effluent gases from the blower during at least a portion of the startup phase of the system, and selectively receives the effluent gases from the cyclone during an operational phase of the system, and dries, cools, and purifies the effluent gases at least in part. A filter receives the effluent gases from the cooling tower, and dries, cools, and purifies the effluent gases at least in part. A second flare selectively receives the effluent gases from the filter during at least a portion of the startup phase of the system, and indicates the presence of the effluent gases by igniting them. An output selectively receives the effluent gases from the filter during the operational phase of the system.

According to various embodiments according to this aspect of the invention, an internal combustion engine receives the effluent gases from the output, and burns the effluent gases to produce motive power. Some embodiments include first and second separate filters, where the first filter receives the effluent gases from the cooling tower, and the second filter receives the effluent gases from the first filter.

According to another aspect of the invention there is described a method for producing effluent gases that are combustible in an internal combustion engine, by receiving biofuel through a loading port at the top of an elongate vessel, where the loading port sized to receive biofuel of at least about eight inches in diameter and twenty inches in length. Dropping the biofuel through a storage zone disposed in the vessel below the loading port, the storage zone providing the biofuel to lower zones within the reactor only via gravity feed. Oxidizing the biofuel into char and precursor gases containing at least carbon dioxide and water vapor in a plasma zone disposed in the vessel below the storage zone, the plasma zone having a tapered configuration that is wider at the top and narrower at the bottom. Providing air to the plasma zone with air nozzles that are radially disposed through a circumference of the vessel at the plasma zone. Receiving the air from an ambient environment and providing the air to the nozzles through a helical air preheater disposed outside the vessel and wrapped around the circumference of the vessel at the plasma zone. Restricting passage of the biofuel through the plasma zone with a reduction zone that is disposed in the vessel below the plasma zone and has a smaller diameter than the plasma zone. Receiving the precursor gases and char from the reduction zone with a char zone disposed in the vessel below the reduction zone, the char zone having a tapered configuration that is wider at the bottom and narrower at the top. Substantially converting the precursor gases to effluent gases comprising hydrogen and carbon monoxide within at least one of the reduction zone and the char zone. Holding the char from the char zone with a grating until the char is oxidized to ash and then permitting the ash to fall through the grating. Retaining the grating in a substantially fixed and immovable configuration during operation. Passing substantially all of the effluent gases through the grating, and then providing the effluent gases to an outlet.

In various embodiments according to this aspect of the invention, the effluent gases are filtered to reduce particulate content. In some embodiments the effluent gases are cooled. In some embodiments the effluent gases are dried. In some embodiments the effluent gases are burned in an internal combustion engine. In some embodiments the effluent gases are used to power an electrical generator.

DRAWINGS

Further advantages of the invention are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:

FIG. 1 is a functional block diagram of a biofuel gasification reactor system according to an embodiment of the present invention.

FIG. 2A is a representation of a first phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 2B is a representation of a second phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 2C is a representation of a third phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 2D is a representation of a fourth phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 2E is a representation of a fifth phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 2F is a representation of a sixth phase of construction of a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 3 is a top plan view of a grating for a biofuel gasification reactor according to an embodiment of the present invention.

FIG. 4 is a perspective view of a top hatch for a biofuel gasification reactor according to an embodiment of the present invention.

DESCRIPTION

System Overview

With reference now to FIG. 1, there is depicted a functional block diagram of a biofuel gasification reactor system 100 according to an embodiment of the present invention. The biofuel, such as wood, is loaded into the reactor 102 and oxidized to produce carbon dioxide and water. The carbon dioxide and water are then reduced in an oxygen deprived region to form hydrogen and carbon monoxide, generally referred to as gases herein.

In some embodiments the gases pass from the reactor 102 to a cyclone 104, in which the gases are, to some extent, cooled, dried, and cleaned. In some embodiments the gases enter the cyclone 104 through a six inch pipe at a bottom peripheral position of the cyclone 104, and exit through a top central position of the cyclone 104. In one embodiment the cyclone 104 is a metal tank that is about eight feet tall and about three feet in diameter. In some embodiments a valve at the bottom of the cyclone 104 allows collected water that condenses out of the gases to be drained off.

In some embodiments the gases are at least initially drawn out of the reactor 102 and through the cyclone 104 by a blower 106. In some embodiments, the blower 106 is only used at the start of the reaction process, while later in the process other forces, such as pressures within the reactor 102 or vacuums formed by the operation of later pieces of equipment as described more fully hereafter, provide all of the motive force required to move the gases through the system 100. In some embodiments the blower 106 selectively passes the gases to at least one of a cooling tower 112 and a condenser 108.

The condenser 108 is used to further cool, dry, and clean the gases. In one embodiment the condenser 108 is a metal cylinder about six feet tall and about four feet in diameter. In some embodiments the gases are introduced into the condenser 108 through a six inch pipe that enters the tank 108 at a position about half way up the length of the sidewall of the tank, and the gases exit the condenser 108 from a central position at the top of the condenser 108. A valve is provided at the bottom of the condenser 108 in some embodiments, so as to drain off the water that condenses out of the gases that flow through the condenser 108.

In some embodiments the condenser 108 provides the gases through a six inch pipe to a first flare 110. The first flare 110 is used, for example, to determine when the reactor 102 is producing combustible gases. At a point in time when the reactor 102 is producing combustible gases, a valve between the blower 106 and the condenser 108 is closed and a valve to the cooling tower 112 is opened, so that the gases are not wasted by just flaring some portion of them off with the first flare 110. This diverts all or a selectable amount of the gases to the cooling tower 112.

In some embodiments the cooling tower 112 is used to further cool, dry, and clean the gases. In one embodiment the cooling tower 112 is a metal cylinder about sixteen feet tall and about three feet in diameter. In some embodiments the gases are introduced into the cooling tower 112 through a six inch pipe that enters the cooling tower 112 at a position about four feet up the length of the sidewall of the cooling tower 112, and the gases exit the cooling tower 112 from a central position at the top of the cooling tower 112. A valve is provided at the bottom of the cooling tower 112 in some embodiments, so as to drain off the water that condenses out of the gases that flow through the cooling tower 112.

In some embodiments the gases that leave the cooling tower 112 are provided to a filter 114, such as through a six inch metal pipe, which filter 114 is used to further cool, dry, and clean the gases. In one embodiment the filter is a rectangular metal box that is about four feet tall, four feet wide, and two feet deep. In some embodiments the gases enter one side of the filter 114 at a position that is about three feet up the sidewall of the filter 114, and exit the filter 114 at a similar position on the opposing side of the filter 114. Inside the filter 114, the gases pass through a first set of one or more particulate filters, such as spun fiberglass filters. In some embodiments the gases then pass through a second set of electrostatic filters before exiting the filter 114, such as through a six inch metal pipe. In some embodiments a condensate drain area is provided at the bottom of the filter 114 and a valve is provided at the bottom of the filter 114, so as to drain off the water that condenses out of the gases that flow through the filter 114. In some embodiments more than one filter 114 is used. In some embodiments two filters 114 are placed in series, and in some embodiments two filters 114 are placed in parallel.

The gases output from the filter 114 are selectively provided, such as through a six inch pipe, to at least one of a second flare 116 and an engine 118. In one embodiment, the gases are initially fed to the second flare 116, so that it can be determined that combustible gases are being provided to that point in the operation of the system 100. In some embodiments, once the presence of gases at the second flare 116 has been determined, the second flare 116 is isolated from the flow of gas, and the gases are provided exclusively to the engine 118, so that the gases are not wasted by just flaring some portion of them off with the second flare 116.

The gases that arrive at the engine 118 are used to power the engine 118. The engine 118 in some embodiments is a spark-type engine, such as an internal combustion engine. The motive power produced by the engine 118 can be used for a variety of purposes. For example, the engine 118 can be used to turn a generator and generate electricity. Alternately, the engine 118 can be used to drive machines such as a pump, winch, or hoist.

The benefit of the system 100 as described is that the system 100 uses a variety of biofuels that can be more easily and economically either found in the vicinity or brought to the location of the facility that is serviced by the system 100.

Reactor

One embodiment of the construction of the reactor 102 is now described, with reference to FIGS. 2A-2F. It is appreciated that other dimensions and constructions are contemplated within the scope of the present invention. Unless otherwise described herein, the components of the reactor 102 are all formed of a durable material, such as steel. However, not all of the components need to be formed of the same material, or even of the same kind of steel. Instead, the material for each component can be selected as desired to fit the environment, purpose, and use of each component, as described herein. It is also appreciated that the various elements of the reactor 102 can be joined together in a variety of different way, even though welding might be specified at various places herein.

With reference now to FIG. 2A, a reactor vessel 200 is formed by fabricating a tube with a radius of about 54 inches and a length of about 200 inches. As depicted in FIG. 1, the right end of the vessel 200 will be disposed in a downward position when the reactor 102 is operational, and is therefore commonly referred to herein as the bottom of the vessel 200. Also as depicted in FIG. 1, the left end of the vessel 200 will be disposed in an upward position when the reactor 102 is operational, and is therefore commonly referred to herein as the top of the vessel 200.

An ignition port 244 is formed through the sidewall of the vessel 200, at a position that is a bit higher than about 62 inches from the bottom end of the vessel 200. The ignition port 244 has a diameter of about 4 inches. A cover that can be selectably opened and closed is fabricated for the ignition port 244.

A series of about 15 equally-spaced holes are drilled through the sidewall of the vessel 200, and an air injection nozzle 204 is welded on the inside of each hole, with each air injection nozzle 204 disposed in a radial orientation. The air injection nozzles 204 have a diameter of about 1.5 inches and a length of about 6 inches. They are disposed at a position of about 44 inches up from the bottom of the vessel 200. A base ring 202 is welded on the inner diameter of the vessel 200. The base ring has a radial width of about 4 inches.

With reference now to FIG. 2B, a cone ring 208 is welded to the vessel 200 at a position that is about 28 inches from the end of the vessel 200. The cone ring 208 has a radial width of about 10 inches. About four grating brackets 210 are welded to the underside of the cone ring 208, equally disposed around the circumference of the cone ring 208, and having a length that is substantially similar to the radial width of the cone ring 208, which in this embodiment is about 10 inches.

A bullet-shaped ash cone 206 is welded onto the cone ring 208. The cylindrical portion of the ash cone 206 has a radius of about 74 inches and a length of about 48 inches, at which point the ash cone 206 has a hemispherical shape with a radius of about 74 inches. A gas exhaust port 248 is formed in the ash cone 206, at a position that is about half-way along the portion of the vessel 200 that extends into the ash cone 206. The gas exhaust port 248 has a diameter of about 6 inches. Additional support structure can be added, as desired, to hold the ash cone 206 to the vessel 200.

With reference now to FIG. 2C, a reduction ring 212 is attached to the inside of the vessel 200 at a position that is about 31 inches up from the bottom of the vessel 200. The reduction ring 212 has a radial width of about 13.5 inches. An ash removal port 218 is formed in the bottom end of the ash cone 206, with a diameter of about 20 inches. A cover that can be selectably opened and closed is fabricated for the ash removal port 218.

A section formed of refractory brick that is mortared smooth extends above and below the reduction ring 212 to a distance of about 31 inches in each direction from the reduction ring 212. The refractory brick section includes a plasma zone 214 and a char zone 216, with a reduction zone 246 disposed between the two at the reduction ring 212. The thickness of the refractory brick is about 4 inches at the tapered ends and about 13.5 inches at the tapered center portion. Thus, the reduction zone 246 has a diameter of about 27 inches. The air injection nozzles 204 are positioned to extend just into the plasma zone 214, at a position along the length of the vessel 200 where the refractory brick is about 6 inches thick. Both the reduction ring 212 and the base ring 202 help to support the weight of the refractory brick when the reactor 102 is in its upright position.

In one embodiment the refractory brick of the plasma zone 214, reduction zone 246, and char zone 216 forms an hour-glass cross section. In other words, the inner walls of the plasma zone 214 have a somewhat paraboloid cross-sectional shape to them, as do the inner walls of the char zone 216, which are substantially mirror-image of one another at the reduction ring 212. This particular shape provides great benefits in staging the fuel through the plasma zone 214, reduction zone 246, and char zone 216 in such a way that it is appropriately oxidized and the precursor gases are efficiently and substantially converted into effluent gases.

With reference now to FIG. 2D, a grating 222 is placed over the bottom end of the vessel 200, and is held in place by supports 220, such as chains suspended from the grating brackets 210. The grating 222 is sized so as to completely cover the bottom end of the vessel 200, but fit within the inner diameter of the ash cone 206. The center of the grating 222 can be supported, such as by a length of about 1.5 inch wide angle bracket extending completely across the grating 222.

In some embodiments the grating 22 is formed in sections so as to fit into the reactor 102 through the service port 224. For example, the grating 222 can be formed of three sections that are sized so that they can fit through the service port 224 to be installed or removed, and then can be assembled inside of the ash cone 206 and hung on the grating chains 220 so that the grating 222 is held in its proper position beneath the char zone 216 at the bottom of the vessel 200. In one embodiment the grating 222 is held fixed and immovable during operation of the reactor 102.

More detail for the grating 222 is provided in FIG. 3. The grating 222 has grating pegs 234, to which the grating supports 220 are attached. The bars 236 of the grating 222 are rounded, so that char that decomposes on top of them can fall more easily through the grating 222 as it reduces in size. The bars 236 in one embodiment are formed of about 0.75 inch diameter solid stainless steel rods set at a spacing of about 0.75 inches. The spacing between the bars 236 is selected so as to retain char above a desired size within the char zone 216, and to allow char below a desired size to drop into the ash cone 206, from whence it can eventually be removed through the ash removal port 218.

One problem with the design of some gasification reactors is that they cannot use large biofuels, such as the logs described above, and the gratings must be agitated so as to not become clogged with ash. Putting large biofuels into such reactors tends to increase the clogging problems with the grating. By selecting characteristics such as those described above in regard to the grating 222, the reactor 102 as described herein is able to accommodate large biofuel sizes, and yet operate without clogging the grating 222, even without any means by which the grating 222 is agitated or shaken to clear it. It is noted that this is a valuable benefit of the present system 100 as described, because the size of the reactor 102 would make it very difficult to shake it, and the inclusion of an agitator for the grating 222 would create additional complexity and expense.

With reference now to FIG. 2E, a service port 224 is formed in the side of the ash cone 206, with a position where the top of the service port 224 (when the reactor 102 is disposed in its upright position) is about the same level as the bottom of the vessel 200, where the grating 222 is disposed. The service port 224 has dimensions of about 32 inches square. A cover that can be selectably opened and closed is fabricated for the service port 224.

An annular preheater 226 is placed around the vessel 200 just above the ash cone 206. The annular preheater 226 receives ambient air through an air inlet port 228, circulates it around the vessel 200, such as in about three helical passes around the circumference of the vessel 200, and provides it to the plasma zone 214 through the air injection nozzles 204. During the operation of the reactor 102, the annular preheater 226 heats the air that is provided for the gasification of the biofuel within the reactor 102. In some embodiments, the air inlet port 228 has a diameter of about 6 inches, and the circumferential passes of the annular preheater 226 have cross-sectional dimensions of about 8 inches square. In some embodiments a blower is connected to the air inlet port 228, so as to force air into the reactor 102.

With reference now to FIG. 2F, the reactor 102 is depicted in its operational orientation. Legs 230, or some other means, are attached so as to keep the reactor 102 upright. In some embodiments, the legs 230 are formed of about 6 inch diameter steel pipe, with a length of about 222 inches. Support plates with a thickness of about 0.3.75 inches can be secured near the top of the legs 230, and platform feet with a size of about 24 inches square and about 2 inches thick can be secured at the bottom of the legs 230. A personnel platform 232 with safety railings and an access ladder are provided at the top of the reactor 102.

FIG. 4 provides detail in regard to the top port 242, through which the biofuel is loaded into the reactor 102. Top port has dimensions of about 24 inches square, and is covered with a door 240 that is about 27 inches square and about 0.375 inches thick. The door 240 slides on roller bearings along rails 238, such as about 1.5 inch diameter tubes. The rails 238 and door 240 are formed such that when the door 240 is in position above the top port 242, a relatively tight seal is formed.

Operation

In one method of operation, the reactor 102 is loaded through the top loading port 242 to the top of the vessel 200 with biofuel. In one embodiment the biofuel is wood, such as logs or split logs that are about four inches to about eight inches in diameter, and from about sixteen inches to about twenty inches in length. In other embodiments, wood briquettes or pucks are used as the biofuel. In other embodiments, animal waste or vegetation is used. The biofuel need not be dried, but in general, drier fuel presents a better reaction effluent. Once the reactor 102 is loaded, the door 240 on the top of the reactor 102 is closed by sliding it along the rails 238.

During the startup phase of operation, the blower 106 is started, the valves to the first flare 110 and the second flare 116 are open, and the valves to the cooling tower 112 and the engine 118 are closed. An ignition source is used to ignite the biofuel within the reactor 102. In one embodiment, a rag is soaked with about one quart of diesel fuel, lit, and tossed into the reactor 102 through the ignition port 244, which is then closed. The draw from the blower 106 sucks air in through the air inlet port 228, the annular preheater assembly 226, and the air injector ports 204, pulling the flaming rag into and igniting the biofuel in the reduction zone 246.

The startup phase lasts approximately six hours, after which combustible gases are produced in sufficient quantity by the reactor 102. During the startup phase, the biofuel is gasified in a plasma ball that forms in the plasma zone 214. If the vessel 200 has a diameter that is substantially bigger than that as described herein, then the plasma in the plasma zone 214 tends to form a ring instead of a ball, and the gasification of the biofuel is less efficient. If the vessel 200 has a diameter that is substantially smaller than that as described herein, then the reactor 102 is not able to receive biofuel of the large size as described herein. The temperature within the plasma zone 214 reaches approximately two thousand degrees Fahrenheit, depending upon the biofuel that is used and the amount of oxygen that is present.

The restricted diameter of the reduction zone 246 tends to prevent the biofuel from falling down past the plasma zone 214 until it is partially converted to a char, at which point it falls through the reduction zone 246 and into the char zone 216, where it is stopped by the grating 222, and the charring process continues. The temperature in the char zone 216 is not as high as the temperature in the plasma zone 214. The gases are drawn down through the reactor 102 into the ash cone 206 and out through the gas outlet port 248.

The first flare 110 can be configured so that a flame ignites automatically when volatile gases are present there or, alternately, the output at the first flare 110 can be repeatedly manually checked for volatility. At the end of the startup period, the first flare 110 will ignite, indicating that the gases are ready to move through the rest of the system 100.

At the end of the startup period, when volatile gases are detected at the first flare 110, the valves to the first flare 110 are closed, the flame at the first flare 110 is extinguished, and the valves to the cooling tower 112 are opened. When the second flare 116 lights, the gas has made its way to that point in the system 100. Similar to that as described above in regard to the first flare 110, the second flare 116 can be configured so that a flame ignites automatically when volatile gases are present there or, alternately, the output at the second flare 116 can be repeatedly manually checked for volatility.

At this point, the valves to the second flare 116 are closed, the flame at the second flare 116 is extinguished, the valves to the engine 118 are opened, and the engine 118 is started, using the gas as its fuel. In some embodiments about a 1:1 ratio of gases to air is used as the intake mix for the engine 118. Once the engine 118 is running, the valves around the blower 106 can be selectively adjusted to by-pass the blower 106, which can then be shut down, as the draw from the intake from the engine 118 is sufficient to provide all the suction that is necessary to draw the gases through the system 100.

The reactor 102 can be opened at the top port 242 during processing, to replace biofuel that has fallen by gravity through the reactor 102 as it has been converted first to char and then to ash in the process. In some embodiments it is preferred to reseal the door 240 on the port 242 once the biofuel reloading process is completed. This can be done again and again as the biofuel is spent, such that the output of gases from the system 100 is substantially continuous. In other words, it is not necessary to stop production of the gases to open the top port 242 and refuel the reactor 102. The biofuel can be provided to the top of the reactor 102 such as with a conveyor belt or other means.

While it is best to start with a relatively dry biofuel in some embodiments, the various components of the system 100 tend to reduce the amount of water in the gases to an acceptable level. For example, in some embodiments the gases delivered to the engine 118 have a relative humidity that is no more than about 20 percent, and are filtered for particulates that are no greater than about 20 microns. Further, the gases are cooled through the system 100 from an initial exit temperature from the reactor 102 of about 600 degrees Fahrenheit to a delivery temperature at the engine 118 of about 80 degrees Fahrenheit. A reactor 102 of the size as described herein can produce about 15,000 cubic feet per minute of volatile gases. However, the engine 118 might only consume about 3,000 cubic feet per minute of the gases. Thus, the system 100 in some embodiments is capable of supplying as many as about 5 engines simultaneously, or alternately, could be scaled to drive the desired number of engines 118, or to merely store the gases produced.

The foregoing description of embodiments for this invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

REFERENCES

• 100 Biofuel Gasification Reactor System
• 102 Reactor
• 104 Cyclone
• 106 Blower
• 108 Condenser
• 110 First Flare
• 112 Cooling Tower
• 114 Filter
• 116 Second Flare
• 118 Engine
• 200 Vessel
• 202 Base Ring
• 204 Air Injection Nozzles
• 206 Ash Cone
• 208 Cone Ring
• 210 Grating Brackets
• 212 Reduction Ring
• 214 Plasma Zone
• 216 Char Zone
• 218 Ash Removal Port
• 220 Grating Chains
• 222 Grating
• 224 Service Port
• 226 Annular Preheater
• 228 Air Inlet Port
• 230 Reactor Legs
• 232 Reactor Platform
• 234 Grating Pegs
• 236 Grating Bars
• 238 Top Port Rails
• 240 Top Port Door
• 242 Top Port
• 244 Ignition Port
• 246 Reduction Zone
• 248 Gas Exhaust Port

Claims

1. A biofuel gasification reactor for producing effluent gases that are combustible in an internal combustion engine, the reactor comprising:

an elongate vessel disposed in an upright orientation and having a top, a bottom, and a diameter,

a biofuel loading port at the top of the vessel, the loading port having a cover, the loading port sized to receive biofuel of at least about eight inches in diameter and twenty inches in length,

a biofuel storage zone disposed in the vessel below the loading port, the storage zone for storing the biofuel and providing the biofuel to lower zones within the reactor only via gravity feed,

a plasma zone disposed in the vessel below the storage zone for oxidizing the biofuel into char and precursor gases containing at least carbon dioxide and water vapor, the plasma zone having a tapered configuration that is wider at the top and narrower at the bottom,

air nozzles radially disposed through a circumference of the vessel at the plasma zone for providing air to the plasma zone,

a helical air preheater disposed outside the vessel and wrapped around the circumference of the vessel at the plasma zone for receiving air from an ambient environment and providing the air to the nozzles,

a reduction zone disposed in the vessel below the plasma zone for receiving the precursor gases and char from the plasma zone, and having a diameter that is less than the diameter of the vessel,

a char zone disposed in the vessel below the reduction zone for receiving the precursor gases and char from the reduction zone, the char zone having a tapered configuration that is wider at the bottom and narrower at the top,

the precursor gases being substantially converted to effluent gases comprising hydrogen and carbon monoxide within at least one of the reduction zone and the char zone,

a grating disposed at the bottom of the vessel below the char zone for holding the char until it is oxidized to ash and then permitting the ash to fall through the grating, the grating covering the entire bottom of the char zone, the grating disposed in a substantially fixed and immovable configuration during operation of the reactor, the grating for passing substantially all of the effluent gases there through,

an ash cone disposed beneath and partially around the vessel for receiving the ash through the grating, the ash cone having a service port formed therein, where the size of the service port is smaller than the size of the grating, the grating formed in pieces that can be disassembled and passed through the service port and reassembled within the ash cone, and

an effluent gas outlet port disposed in the ash cone above the bottom of the vessel for providing the effluent gases to an internal combustion engine.

2. The reactor of claim 1, wherein the plasma zone, reduction zone, and char zone are all formed of refractory brick inside the reactor vessel.

3. The reactor of claim 1, wherein the reactor vessel is formed of steel.

4. The reactor of claim 1, wherein the grating is formed of steel.

5. The reactor of claim 1, wherein the reduction zone has a diameter of about 27 inches.

6. The reactor of claim 1, wherein the vessel has a diameter of about 108 inches.

7. The reactor of claim 1, wherein the vessel has a length of about 200 inches.

8. The reactor of claim 1, wherein the plasma zone and the reduction zone each have a height of about 28 inches.

9. The reactor of claim 1, wherein the grating is about 24 inches square.

10. The reactor of claim 1, wherein the preheater makes about three complete revolutions around the vessel.

11. A biofuel gasification system comprising:

the reactor of claim 1, for producing effluent gases,

a cyclone for receiving the effluent gases from the reactor, and for drying, cooling, and purifying the effluent gases at least in part,

a selectively by-passable blower for drawing the effluent gases from the cyclone during a startup phase of the system,

a condenser for selectively receiving the effluent gases from the blower during at least a portion of the startup phase of the system, and for drying, cooling, and purifying the effluent gases at least in part,

a first flare for receiving the effluent gases from the condenser and for indicating the presence of the effluent gases by igniting them,

a cooling tower for selectively receiving the effluent gases from the blower during at least a portion of the startup phase of the system, and for selectively receiving the effluent gases from the cyclone during an operational phase of the system, and for drying, cooling, and purifying the effluent gases at least in part,

a filter for receiving the effluent gases from the cooling tower, and for drying, cooling, and purifying the effluent gases at least in part,

a second flare for selectively receiving the effluent gases from the filter during at least a portion of the startup phase of the system, and for indicating the presence of the effluent gases by igniting them,

an output for selectively receiving the effluent gases from the filter during the operational phase of the system.

12. The system of claim 11, further comprising an internal combustion engine for receiving the effluent gases from the output, and burning the effluent gases to produce motive power.

13. The system of claim 11, wherein the filter further comprises first and second separate filters, the first filter for receiving the effluent gases from the cooling tower, and the second filter for receiving the effluent gases from the first filter.

14. A method for producing effluent gases that are combustible in an internal combustion engine, the method comprising the steps of:

receiving biofuel of at least about eight inches in diameter and twenty inches in length through a loading port at the top of an elongate vessel,

dropping the biofuel through a storage zone disposed in the vessel below the loading port, the storage zone providing the biofuel to lower zones within the reactor only via gravity feed,

oxidizing the biofuel into char and precursor gases containing at least carbon dioxide and water vapor in a plasma zone disposed in the vessel below the storage zone, the plasma zone having a tapered configuration that is wider at the top and narrower at the bottom,

providing air to the plasma zone with air nozzles that are radially disposed through a circumference of the vessel at the plasma zone,

receiving air from an ambient environment and providing the air to the nozzles through a helical air preheater disposed outside the vessel and wrapped around the circumference of the vessel at the plasma zone,

restricting passage of the biofuel through the plasma zone with a reduction zone that is disposed in the vessel below the plasma zone and has a smaller diameter than the plasma zone,

receiving the precursor gases and char from the reduction zone with a char zone disposed in the vessel below the reduction zone, the char zone having a tapered configuration that is wider at the bottom and narrower at the top,

substantially converting the precursor gases to effluent gases comprising hydrogen and carbon monoxide within at least one of the reduction zone and the char zone,

holding the char from the char zone with a grating until the char is oxidized to ash and then permitting the ash to fall through the grating, retaining the grating in a substantially fixed and immovable configuration during operation,

passing substantially all of the effluent gases through the grating, and

providing the effluent gases to an outlet.

15. The method of claim 14, further comprising receiving the effluent gases at the outlet and filtering them to reduce particulate content.

16. The method of claim 14, further comprising receiving the effluent gases at the outlet and cooling them.

17. The method of claim 14, further comprising receiving the effluent gases at the outlet and drying them.

18. The method of claim 14, further comprising receiving the effluent gases at the outlet and burning them in an internal combustion engine.

19. The method of claim 14, further comprising receiving the effluent gases at the outlet and using them to power an electrical generator.

20. The method of claim 14, further comprising receiving the effluent gases at the outlet, filtering, drying, and cooling them, and burning them in an internal combustion engine to power an electrical generator.