WO2009015075A2

WO2009015075A2 - Apparatus to convey material to a pressurized vessel and method for the same

Info

Publication number: WO2009015075A2
Application number: PCT/US2008/070626
Authority: WO
Inventors: Larry E. Pearson
Original assignee: Pearson Larry E
Priority date: 2007-07-21
Filing date: 2008-07-21
Publication date: 2009-01-29
Also published as: WO2009015075A3; US20090019771A1; CA2731715A1

Abstract

The present invention relates to an improved apparatus and method for conveying fibrous, solid and slurry materials, such as granulated wood, rice hulls, chopped cane and the like, to a pressurized vessel, wherein the material being conveyed is compacted in the feeder in a controlled manner to create a seal at the feeder exit into the pressurized vessel whereby the processing pressure in the vessel is maintained. The invention is particularly useful when used in conjunction with a biomass reactor for the production of gas selectively rich in hydrogen and carbon containing components, such as carbon monoxide, carbon dioxide and methane, which in turn, may be converted into a select end product fuel, such as methanol or ethanol or used as a feed gas for an industrial power plant, such a the biomass reactor for producing gas.

Description

PCT PATENT APPLICATION

TITLE OF THE INVENTION

APPARATUS TO CONVEY MATERIAL TO A PRESSURIZED VESSEL AND METHOD FOR THE SAME

INVENTOR

Larry E. Pearson, a U.S. citizen and resident of Winona, Mississippi

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Provisional Application for Patent, Serial Number 60/951,198. filed July 21, 2007, which application is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Funding from Department of Energy under grant DE-FG36-02GO 12025 was received in conjunction with the development of this technology.

REFERENCE TO A "MICROFICHE APPENDIX" Not applicable

BACKGROUND OF THE INVENTION

The present invention relates to an improved apparatus and method for conveying fibrous, solid and slurry materials, such as granulated wood, rice hulls, chopped cane and the like, to a pressurized vessel. The material being conveyed is compacted in the feeder in a controlled manner to create a seal at the feeder exit to the pressurized vessel which maintains the pressure in the vessel. The invention is particularly useful when used in conjunction with a biomass reactor for the production of gas selectively rich in hydrogen and carbon containing components, such as carbon monoxide, carbon dioxide and methane, which in turn, may be converted into a select end product fuel, such as methanol or ethanol or used as a feed gas for an industrial power plant, such as the biomass reactor for producing gas described in U.S. Patent No. 6,767,375 owned by the inventor of the present invention.

Gasification of biomass material such as wood, woodchips, sawdust, wood charcoal, rice, sugar cane hulls and other particulate cellulosic materials has become of increasing interest and importance because of the volatility of petroleum prices, dwindling of fossil fuels, such as domestic petroleum and natural gas resources and the increased dependence of the United States on international imports of these fuels. Gasification of coal and biomass has been practiced for over one hundred years and there are many varieties and types of gasifiers and methods of gasification. One method of gasification applicable to biomass material is pyrolysis. Pyrolysis is the breakdown of the biomass by heat at elevated temperatures (e.g. , about 400 to about 1200 degrees Fahrenheit) to yield an intermediate gas which is ultimately transformed into a market fuel (gas or liquid such as methane or ethanol). Inclusion of a transport gas, such as oxygen or steam, during the pyrolysis, assists in the production of an intermediate gas containing carbon monoxide, carbon dioxide and hydrogen, useful in later conversion into fuel such as ethanol, methanol, ammonia or methane. Similarly, other gas additions, such as air or nitrogen, may be used for synthesis gas having other makeup required for different end products.

As mentioned, the present invention is particularly useful when used in conjunction with the biomass reactor for producing gas as described in U.S. Patent No. 6,767,375 ('"375 Patent") owned by the inventor of the present invention. The '375 patent provides an improved method and apparatus for producing a synthesis gas from a biomass feed material. In one aspect, the '375 patent incorporates a reactor vessel heated, at least in part, by a heat source such as an electric or natural gas heating unit. The reactor vessel generally includes a helical coil or conduit of many turns utilized for carrying the biomass feed material and an appropriate transport gas, throughout which the pyrolytic process is performed. Some embodiments of the helical coil may have a cooling system associated with at least a portion of a support system interconnecting the helical coil with the reactor vessel.

The many turns of this helical coil may be disposed in the vessel in a number of appropriate locations, but are preferably disposed adjacent a sidewall of the reactor vessel. This preferred arrangement of the coil relative to the reactor vessel may be said to provide an air gap between the coil and the vessel sufficient to produce convective heating. The coil generally receives a feed of the biomass material, preferably in ground or granulated form, which is mixed and transported through the reactor coil utilizing the transport gas. In some embodiments, the transport gas may provide heat and/or chemical support to the pyro lysis process in addition to the externally supplied heat that is utilized to transform the biomass material into a target synthesis gas in the reactor coil. The rate of and control over the pyrolysis process in the reactor coil are preferably effected by the inclusion of separated radiant and convective heat zones in the reactor vessel. These heat zones, at least in one embodiment, may generally be determined by the location of a heat shield disposed in the vessel. This heat shield may exhibit any of a number of appropriate designs. For instance, in one preferred embodiment, the heat shield includes an at least generally cylindrical section. Moreover, this heat shield may be disposed in any effective location relative to the coil. It is, however, preferred that the heat shield be located at least generally, concentrically of the coil. Further, it is also generally preferred that this heat shield be located in an upper region of the vessel above the heat source. The heat shield preferably includes a truncated conical section disposed toward a bottom of the heat shield (closed at an end nearest the heat source) to better establish transition between the radiant and convective heat zones and to facilitate convective heating in the respective zone.

Preferably, the reactor vessel includes a pressurized mixing vessel in which the biomass feed material is collected, mixed and supplied to the reactor coil. This pressurized vessel may include a number of appropriate mechanisms capable of maintaining a seal against a loss of operating pressure within the mixing chamber while promoting the biomass feed material and/or the transport gas to pass therethrough.

It is desirable to mix the transport gas and biomass feed together in a pressurized vessel before they enter the reactor. A transport gas utilized to mix and transport the biomass feed and carry it to the reactor is input into the pressurized vessel. The biomass feed materials are generally added to the pressurized vessel at atmospheric pressure, or at some lower pressure than that of the mixer; thus, there would be backflow of the transport gas through the feeding mechanism and into the vessel containing the feed material unless there is an adequate seal between the vessels.

In the '375 patent, the material is introduced into the pressurized vessel from a hopper through a veined rotary valve. The hopper contains bulk raw material which is supplied to the rotary valve by means of a conventional metering rotary valve feeding the amount of biomass feed material to the pressurized vessel preferably in a manner and/or at a rate sufficient for a particular gas output. In order to ensure that no significant amount of build up of biomass feed material occurs in the hopper at the rotary valve, the rotary valve is preferably operated at a higher RPM than the metering valve.

As noted, one function of the rotary valve is to at least generally seal the interior of the pressurized vessel to the atmosphere. This generally helps maintain gas pressure within the system as well as promote the pressurized feed of mixed biomass and transport gas traveling from the pressurized vessel to the reactor. The biomass feed is introduced into the pressurized vessel by means of a rotary valve which may be rotated utilizing any appropriate means, such as an electric motor. The rotary valve may be said to facilitate the supply of material in being moved into the lower portion of the drop tube and toward the bottom of the pressurized vessel. Incidentally, the metering valve and the rotary valve are interconnected by an upper portion as the drop tube. The drop tube may be said to contain the biomass feed as a transit to and from the rotary valve. What may be characterized as a mating of veins with side walls of the rotary valve is such that a seal against back pressure is at least generally provided thereby between the lower and upper portions respectively of the drop tube. This seal of sorts may be said to assist in maintaining the pressure of the incoming transport gas to prevent over heating of the rotary valve.

Due to the nature of the feed materials, they may lump together and flow non- uniformly into the mixer. This non-uniform flow can clog the feeding mechanism and create problems maintaining pressure in the mixer. The '375 patent system utilizes a rotary vane valve as a feeder which has several issues. One issue with that design is pocket plugging. The feed material initially falls into the pockets of the valve. This material is compressed as the pressure from the system enters the pockets. Moisture in the material or from the system transport gas causes the material to stick in the pocket. The material does not exit the pocket at the discharge position, but is carried around to the feed inlet position where less material can enter the pocket. This continues until the pocket is full of material and the feed system is completely plugged.

Temperature variations also cause problems for the rotary valve feeder. The heat from the transport gas is transferred to the rotary valve feeder which causes expansion and contraction. The lower portions of the rotary valve are exposed to greater heat than the lower portions; therefore, the expansion is not uniform throughout the valve. The seal created by the rotary valve is dependent on a very close tolerance between the rotating vanes and the rotary valve body. Temperature variations in the rotary valve components change these tolerances and cause either loss of pressure and leakage (if the tolerance is increased) or damage to the valve and seizing of the valve (if the tolerance decreases).

When using the rotary valve feeder, after the material is added to the pocket that pocket is pressurized before the material is deposited in the pressurized vessel. If this step is skipped, the pressure in the pressurized vessel may prevent the material from exiting the pocket at the valve outlet. Another issue, is that if the pressurized vessel contains moist gas, that gas seeps into the pocket adding moisture to the feed material and possibly causing clumping to occur. A inert gas such as nitrogen is typically used to pressurize the pocket. Nitrogen dilutes the transport gas and requires larger system components to handle the required amount of transport gas plus the additional inert gas. The present invention eliminates the need to pressurize the feeder.

After discharging the material, the rotary valve pockets fill with pressurized transport gas. The pressurized transport gas must be evacuated before the valve pocket returns to the feed inlet position. If not, the transport gas will discharge into the feed inlet area and a smaller amount of feed material or none at all will be able to enter the rotary valve pocket. The discharge of transport gas containing moisture at the feed inlet introduces moisture into the feed material and may cause plugging at the feed inlet.

The present invention is an improvement over the '375 patent feed system and allows for conveying fibrous solid and slurry materials, such as biomass materials, in a uniform matter. It utilizes the material itself to maintain the seal, thus allowing a vessel, such as a mixer, to maintain its pressure while material is being added to it. The present invention solves the challenges listed above by blocking flow of the transport gas from the pressurized vessel into the feeder with the material plug, hi the present invention, the material is only exposed to the transport gas beyond the conveying means at the point where it is discharged, so there is no potential for moist feed material to plug the conveying means. Likewise, a close tolerance between rotating and stationary parts is not critical to maintain a seal. Additionally, the moving parts do not rotate past stationary parts which are at different temperatures as with the rotary valve. Thus, the challenges presented by the temperature variations and the rotary valve are eliminated. The conveying mechanism of the present invention does not contact the transport gas thus the exhaust cycle for removing trapped transport gas from the empty rotary valve pocket is eliminated.

There are numerous commercial examples of auger systems such as those which feed plastic pellets into injection molding machines, hi those systems, the plastic pellets melt and flow uniformly into the auger which transports the plastic into the injection molding machine. The present invention differs from those systems because it is able to handle many different compositions of fibrous solid and slurry materials which otherwise tend to flow non- uniformly and provides a uniform flow of material into a pressurized vessel.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an improved apparatus and method for conveying fibrous solid and slurry materials into a pressurized vessel while maintaining the pressure in that vessel by utilizing the material to create a seal. One use of the present invention is to feed material into a flowing gas stream at a pressure. Another use of the present invention is to feed material into a vessel, grinder, processing machine or the like which is at a pressure.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a side view of the conveying apparatus including a cross section of the discharge housing.

Figure 2 is a side view of the conveying apparatus including a cross section of the discharge housing with a cut away showing the auger.

Figure 3 is a side, cross sectional view of the discharge housing showing the conical end being forced out of the material retention chamber.

Figure 4 is a side, cross sectional view of the discharge housing showing the material retention chamber open and material exiting the material retention chamber.

Figure 5 is a side, cross sectional view of the discharge housing showing the material retention chamber closed off by the conical end.

Figure 6 is a perspective view of the conveying apparatus as attached to the pressurized vessel.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1, the present invention includes an auger 4 enclosed in a pipe 1 with an inlet 5 and an outlet 10 for transporting biomass material. (Figure 2 shows the auger 4) The auger 4 is powered by a drive motor 6 (See Figure 6). The pipe 1 and auger 4 are made of any durable material such as carbon steel or stainless steel. The abrasiveness and hardness of the material should be considered by those skilled in the art when determining the particular materials of construction of the pipe 1 and auger 4. Because the auger 4 is forcing the biomass material against the interior walls of the pipe 1, those more highly abrasive materials may cause considerable frictional wear on the interior walls of pipe 1 and auger 4. Those skilled in the art should recognize the higher the speed of auger 4, the greater the likely wear on the pipe 1 and auger 4. In embodiments where the material is highly abrasive, the speed of auger 4 (and thus the material feed speed) should be relatively minimized to reduce wear to a tolerable level. In one embodiment, the material is a fibrous, biomass feed, such as saw dust — a byproduct of processing lumber for use in furniture production or as building material at commercial sawmills, but the material could be any solid or slurry biomass material.

The inlet 5 is connected to a metering device (not shown) which controls the feed rate of the material to be conveyed by the auger 4 to the pressurized vessel 2. The metering device can be any commercially available metering device such as a metering screw, belt feeder, rotary valve or the like, such as the Fuller-Kovako rotary feeder illustrated in U.S. Patent No. 6,767,375). The rate of material transfer is not controlled by the auger 4 speed, but by the speed of the metering device; therefore, to avoid accumulation of feed material at the inlet 5, the auger 4 should be operated at a speed capable of handling more material than is being conveyed by the metering device. The ratio of metering device outlet speed to auger 4 speed is dependent on many parameters such as size, type of material, and type of metering device. For example, in one embodiment, the auger runs between 10 % to 33% faster than the metering device.

The outlet 10 is adjacent to a discharge housing 15 at a first side opening 16 in the discharge housing 15. The discharge housing 15 also has a second side opening 17 and a bottom opening 18. A material retention chamber 20 is disposed between the outlet 10 of the pipe 1 and the first side opening 16 of the discharge housing 15. The material retention chamber 20 extends into the discharge housing 15. hi one embodiment the material retention chamber 20 is created by a portion of the pipe 1 which extends beyond the auger 4. In another embodiment, the material retention chamber 20 is a separate section of pipe attached to the outlet 10 of pipe 1. The material retention chamber 20 has a chamber inlet 21 and a chamber outlet 22.

A piston 25 is connected to the discharge housing 15 at the second side opening 17. The piston 25 is comprised of a cylinder 26 and a plunger 27 which is enclosed in the cylinder 26. The plunger 27 moves horizontally within the cylinder 26 when pressure is applied to either end of the cylinder 26. The plunger has a conical end 28 which extends into the discharge housing 15 and a rear end 29 which is enclosed in the cylinder 26. The conical end 28 may be made of plastic or metal and has a smooth surface, however having a surface sufficiently suitable wear resistant to withstand the frictional flow of the compressed biomass material, hi one embodiment, pressure is applied to the rear end 29 of the cylinder 26 by an air or hydraulic pressure system through pressure fitting 32. The pressure setting is controlled as part of the overall control of the conveying system. The air or hydraulic pressure setting can be controlled or correlated to the power input of the auger 4, for instance by monitoring the drive motor 6. In another embodiment, the pressure control can be set to adjust the air or hydraulic load to keep the pressure higher.

Referring now to Figure 2, the pressure on the cylinder is set so that the plunger 27 extends out of the cylinder 26 and into the discharge housing 15 far enough that the conical end 28 is inserted into the chamber outlet 22 of the material retention chamber 20 closing the material retention chamber 20 off from the discharge housing 15. The amount of pressure set on the rear end 29 of the plunger 27 and the horsepower delivered by the auger 4 varies according to the characteristics of the material, such as particle size, moisture, compressibility, friability, and elasticity to name a few. For example, finer, dry materials require more pressure to compress to a consistency where the gas will not permeate through void spaces in the mixture and the auger 4 must deliver more horsepower. Coarse, wet materials require less pressure to compress because the moisture fills void spaces more readily and prevents any gas from permeating through the plug and the auger 4 can deliver less horsepower. The total horsepower delivered by the auger must overcome both the wall friction and the cone pressure. The cone pressure adds to the wall friction to give the required total compaction power.

As material is transferred through the pipe 1 by the auger 4, it collects in the material retention chamber 20 until material retention chamber 20 is filled. Referring now to Figure 2, as the material fills the material retention chamber 20, the solid particles are compressed together creating a material plug as at 23 in the material retention chamber 20. The build up of material in material retention chamber 20 exerts pressure on the conical end 28. When enough material has built up in the material retention chamber 20 that the pressure on the conical end 28 exceeds the pressure setting on the rear end 29, the material forces the plunger 27 to move horizontally in the cylinder 26, opening the chamber outlet 22 so that material exits the material retention chamber 20 into the discharge housing 15 as shown in Figures 3 and 4. The drive motor 6 on the auger 4 should be sized to successfully drive the auger 4 against the pressure created by piston 25 and force the material to compact creating material plug 23.

The material plug 23 thus creates a seal between the pipe 1 and the discharge housing 15 preventing the backflow of gas from the pressurized vessel 2 into the pipe 1 when the conical end 28 is not itself inserted into the material retention chamber 20. Although some material is discharged, the auger 4 feeds enough new material into the material retention chamber 20 to maintain the material plug 23. The pressure on rear end 29 forces the plunger 27 to move horizontally in the cylinder 26, extending the plunger 27 far enough into the discharge housing 15 that it is reinserted into the chamber outlet 22. (See Figure 5) The pressure setting on the rear end 29 of the plunger 27 and the speed of the auger 4 are parameters that are controlled to maintain the material plug 23 and the seal it creates. These two parameters determine the degree of compaction of the material and the force exerted by the material on the walls of the pipe 1. The speed of the auger 4 should be set such that the material discharge rate exceeds the rate of permeation of the pressurized gas from pressurized vessel 2 through the plug 23. In one embodiment the auger 4 runs at a constant speed to ensure no accumulation of material at the inlet 5 and a constant rate of discharge of material at chamber outlet 22. In another embodiment, the auger 4 speed varies, but is dependent on the metering device speed and is maintained at a speed slightly greater than the metering device speed. This would be particularly useful in situations where the operating parameters of the pressurized vessel fluctuate. In yet another embodiment, the auger 4 speed will be set to never drop below a minimum speed in order to maintain the plug 23 and seal and prevent the loss of system pressure. This would also be particularly useful in situations where the operating parameters of the pressurized vessel fluctuate.

The amount of pressure on the rear end 29 of the plunger 27 is dependent on the characteristics of the feed material and the pressure of the pressurized vessel 2. In one embodiment, the pressure on the rear end 29 is varied by adjusting the horsepower delivered by the auger or the speed of the auger. In another embodiment, the pressure on the rear end 29 is 30 psig greater than the maximum system pressure in the pressurized vessel 2.

The size of the material retention chamber 20 and the distance from the chamber outlet 22 and the conical end 28 of the plunger 27 varies according to the type, grain size, moisture content, and other characteristics of the material. The angle of vertex of a cone is the angle between the axis of the cone and the sloped side of the cone. The larger the diameter of the material retention chamber 20, the greater the degree of the angle of the vertex of the cone of the conical end 28. In embodiments where the material is fine and free flowing, the diameter of the base of conical end 28 should be equal to or greater than the diameter of chamber outlet 22 so that the conical end 28 creates a seal. In other embodiments where the material is drier and resists free flow, the diameter of the base of conical end 28 is less than the diameter of chamber outlet 22.

The pressure, speed of auger controlled to maintain seal 23 is very dependent on the type of material biomass material which is being fed. In the illustrated examples for sawdust, the pressure applied to the plunger should produce a force on the sawdust plug in the range of 15 to 25 psi. This is applicable to examples 1 and 2, below and assumes an auger speed which is 10 to 50% greater than the metering flow. Changes in the compaction nature of the material, as for materials other than the sawdust preferably used, will cause this requirement to change. As stated above, finer materials (including sawdust) will require higher compaction to ensure that the reactor gases do not permeate backwards through the sealing plug 23. This requires plug forces which produce more than the 15 to 40 psi which are used for the materials of the examples. Also, as the reactor pressure increases, a higher force should be used. As may be observed, the force, 15 to 40 psi, is in the range of the pressures sealed against in the illustrative examples. At the start, as the reactor pressure is increased, the plunger force applied to the sawdust should equal the reactor pressure.

Angle of the vertex of cone as compared to the size of chamber varies depending on material type and it is important to ensure that adequate force is applied to the sawdust (and any processed biomass material) to deliver the required compaction to seal against pressure leakage at the plug 23. The cone also serves to break up the plug (i.e., change the direction of the biomass material flow) so that it can enter the steam entrainment area. As the size of the chamber increases (relative to the size of the particles) the cone angle must also increase. It is appropriate angles for materials other than the sawdust of the examples disclosed must be optimized to maintain the flow and plug however it is expected that that the angles will be between 45 and 80 degrees. For very large chamber diameters, it is anticipated that cone angles of slightly less than 90 degrees will be appropriate, albeit appearing as almost be a flat plate. The ultimate cone angle limit is 90 degrees.

Other features of the invention will become apparent in the course of the following examples which are given for illustrations of the invention and are not intended to be limiting thereof.

Example 1: The following is an example of the apparatus of the present invention. The material retention chamber 20 has a three inch diameter, the angle of the vertex of the cone of the conical end 28 is approximately 45 degrees, the utilized motor horsepower is 10 hp, the maximum speed of the auger is 50 rpm, and the auger diameter is 3 inches.. The sawdust wood rate of feed is about 100 pounds per hour and the reactor pressure is 10 psig, the sawdust has an average moisture of about 10% and grain top size of about 1/8 inch.

Example 2: The following is an example of a second embodiment of apparatus of the present invention. The material is sawdust and the material retention chamber 20 has an eight inch diameter, the angle of the vertex of the cone of the conical end 28 is between 70 and 80 degrees. The auger speed is 25 rpm, producing a feed rate of about 800 pounds of sawdust per hour with a reactor pressure of about 40 psig. The useful horsepower of the motor is 15 hp. The auger size is 8 inches in diameter. When the pressurized vessel 2 is run at 30 psig, the pressure on the rear end 29 is 60 psig. It is noted that the 50% increase of horsepower utilized in example 2 represents the ratio of frictional area over the volume for the diameter (3 vs. 8 inches) of the feeders. It is observed that for materials other than sawdust (at the given % of moisture) a starting point is proposed in the application of the data above as adjusted for the coefficient of friction between the "new" material and the material of construction used for the retention chamber. If the "new" coefficient is higher than the coefficient for the sawdust, more horsepower for the drive motor will be required. The increase will be roughly the ratio of coefficients of friction.

It is preferred that the ratio of the metering device flow to auger speed be an auger speed which will deliver 10% more flow than the metering device. Running at less of a ratio usually induces problems with buildup in the auger inlet. It is preferable to generally operate at an auger speed which will deliver 25 to 50% more flow than the metering device. It is noted that running at auger speeds of 200 to 300% of the metering device can be maintained, there is little useful effect. It is observed that to avoid excessive wear in the feeder stream, the 25 to 50% range appears to be appropriate for most applications.

The material exits the discharge housing 15 through the bottom opening 18 which is attached to a pressurized vessel 2 at a feed inlet 31. (See Figure 2) In some embodiments, a grinder 32 may be attached to the bottom opening 18 to break up the material as it enters the pressurized vessel 2 through the feed inlet 31 (See Figure 2). A grinder 32 may be included depending on the material and its moisture content. For material that is nominally dry and friable enough to break up on its own, like sawdust, a grinder 32 is not required. However, a grinder 32 is useful for materials which have a higher moisture content and exhibit a paste-like consistency when compacted, like chicken litter. The grinder 32 may be any device which helps break up clumped material and maintain a uniform flow into the pressurized vessel 2. Some examples of acceptable configurations of grinders 32 are a rotating drum against rotating drum or breaker plate, but any commercially available grinder that is contained within the system piping and does not allow accumulation of material above the grinder 32 is acceptable.

Upon start up, material is fed through the auger 4 until material plug 23 is formed. When the pressure exerted by the material plug 23 on the conical end 28 exceeds the pressure on rear end 29, the feed valve 33 connecting the feeder to the feed inlet 31 of the pressurized vessel 2 is opened to start the material feed. (See Figure 6)

Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all alterations and modifications that fall within the true spirit and scope of the invention.

Claims

I claim: 1. A conveying apparatus for adding fibrous solids or slurries to a pressurized vessel comprising: a feed hopper containing a fibrous material for addition to a pressurized vessel; a pipe having an inlet and an outlet, said inlet connected to said feed hopper; an auger for transporting said material from said inlet to said outlet enclosed in said pipe, said auger extending from said inlet to said outlet ; a discharge housing intermediate to said pipe outlet and said pressurized vessel, said discharge housing having a first opening, a second opening, and a third opening; a material retention chamber for collecting and discharging said fibrous material having a chamber inlet and a chamber outlet, said chamber inlet connected to said pipe outlet and projecting through said first opening into said discharge housing such that said material is discharged to said discharge housing when said chamber outlet is not sealed; a piston having a conical end for sealing said material retention chamber outlet, said piston disposed for horizontal movement with respect to said discharge housing and positioned across from said material retention chamber outlet, said conical end engaging said chamber outlet thereby creating a seal when said conical end is engaged and preventing the discharge of said material into said discharge housing; and said pressurized vessel having a feed inlet adjacent to said third opening of said discharge housing whereby said material is transferred from said discharge housing to said pressurized vessel.

2. The conveying apparatus of Claim 1 further comprising: a metering device intermediate to said feed hopper and said pipe inlet for regulating flow of said fibrous material.

3. The conveying apparatus of Claim 1 further comprising: a grinder intermediate to said third opening in said discharge housing and said feed inlet of said pressurized vessel for maintaining uniform flow into said pressurized vessel.

4. The conveying apparatus of Claim 1 further comprising: a feed valve intermediate to said third opening in said discharge housing and said feed inlet of said pressurized vessel for controlling flow into said pressurized feeder.

5. The conveying apparatus of Claim 1 wherein: said conical end of said piston has a angle of vertex of about 45 degrees; and said material retention chamber and chamber outlet have a diameter of about three inches.

6. The conveying apparatus of Claim 1 wherein: said conical end of said piston has a angle of vertex ranging between 45 and 80 degrees; and said material retention chamber and chamber outlet have a diameter ranging between three and eight inches.

7. The conveying apparatus of Claim 1 further comprising: a reactor for processing said material connected to said pressurized vessel.

8. A conveying apparatus for adding biomass feed to a pressurized vessel comprising: a feed hopper containing a biomass material for addition to a pressurized vessel; a pipe having an inlet and an outlet, said inlet connected to said feed hopper; an auger for transporting said material from said inlet to said outlet enclosed in said pipe, said auger extending from said inlet to said outlet ; a discharge housing intermediate to said pipe outlet and said pressurized vessel, said discharge housing having a first opening, a second opening, and a third opening; a material retention chamber for collecting and discharging said fibrous material having a chamber inlet and a chamber outlet, said chamber inlet connected to said pipe outlet and projecting through said first opening into said discharge housing such that said material is discharged to said discharge housing when said chamber outlet is not sealed; a piston having a conical end for sealing said material retention chamber outlet, said piston disposed for horizontal movement with respect to said discharge housing and positioned across from said material retention chamber outlet, said conical end engaging said chamber outlet thereby creating a seal when said conical end is engaged and preventing the discharge of said material into said discharge housing; and said pressurized vessel having a feed inlet adjacent to said third opening of said discharge housing whereby said material is transferred from said discharge housing to said pressurized vessel.

9. The conveying apparatus of Claim 8 further comprising: a metering device intermediate to said feed hopper and said pipe inlet for regulating flow of said biomass material.

10. The conveying apparatus of Claim 8 further comprising: a grinder intermediate to said third opening in said discharge housing and said feed inlet of said pressurized vessel for maintaining uniform flow into said pressurized vessel.

11. The conveying apparatus of Claim 8 further comprising: a feed valve intermediate to said third opening in said discharge housing and said feed inlet of said pressurized vessel for controlling flow into said pressurized feeder.

12. The conveying apparatus of Claim 8 further comprising: a biomass reactor for gasification of said biomass material connected to said pressurized vessel.

13. The conveying apparatus of Claim 8 wherein: a biomass reactor for production of synthesis gas by pyrolysis of said biomass material connected to said pressurized vessel.

14. A method of transferring fibrous solids or slurries to a pressurized vessel utilizing said fibrous material to maintain a seal to prevent backflow of gas from said pressurized vessel which comprises: engaging a conical end of a piston with a material retention chamber intermediate to a feed hopper and a pressurized vessel by applying an external pressure to a rear end of said piston thereby blocking an outlet of said material retention chamber; conveying a fibrous material from a feed hopper to said material retention chamber causing said material to accumulate in said material retention chamber forming a material plug which creates a seal between said feed hopper and said pressurized vessel to prevent backflow of gas from said pressurized vessel, said material plug applies an internal pressure on said conical end of said piston; and forcing said conical end of said piston to disengage with said material retention chamber when said internal pressure exceeds said external pressure thereby discharging said material from said material retention chamber to said pressurized vessel but retaining said material plug in said material retention chamber to prevent backflow of gas from said pressurized vessel.

15. The method of Claim 14 further comprising: metering said material into said material retention chamber at a controlled rate.

16. The method of Claim 14 further comprising: grinding said material that is discharged from said material retention chamber before it enters said pressurized vessel.

17. The method of Claim 14 further comprising: controlling flow of material into said pressurized vessel utilizing a valve intermediate to said material retention chamber outlet and said pressurized vessel.

18. The method of Claim 14 wherein : a vessel pressure of about 30 psig is maintained in said pressurized vessel; and said external pressure applied to said rear end of said piston is about 60 psig.

19. The method of Claim 14 wherein: said fibrous material is a biomass material.

20. The method of Claim 19 further comprising: mixing said biomass material with a transport gas in said pressurized vessel; and transferring said biomass material and transport gas mixture to a biomass reactor for production of a synthesis gas by pyrolysis.