CA2258579A1 - System for burning biomass to produce hot gas - Google Patents
System for burning biomass to produce hot gas Download PDFInfo
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- CA2258579A1 CA2258579A1 CA002258579A CA2258579A CA2258579A1 CA 2258579 A1 CA2258579 A1 CA 2258579A1 CA 002258579 A CA002258579 A CA 002258579A CA 2258579 A CA2258579 A CA 2258579A CA 2258579 A1 CA2258579 A1 CA 2258579A1
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- Prior art keywords
- biomass
- cyclone
- annulus
- air
- combustor
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
- F23G7/10—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of field or garden waste or biomasses
- F23G7/105—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of field or garden waste or biomasses of wood waste
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B45/00—Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
- F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
- F02C3/26—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C7/00—Combustion apparatus characterised by arrangements for air supply
- F23C7/002—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion
- F23C7/004—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion using vanes
- F23C7/006—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion using vanes adjustable
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C7/00—Combustion apparatus characterised by arrangements for air supply
- F23C7/02—Disposition of air supply not passing through burner
- F23C7/06—Disposition of air supply not passing through burner for heating the incoming air
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
- F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
- F23J15/027—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow using cyclone separators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
- F23M5/00—Casings; Linings; Walls
- F23M5/08—Cooling thereof; Tube walls
- F23M5/085—Cooling thereof; Tube walls using air or other gas as the cooling medium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2201/00—Pretreatment
- F23G2201/10—Drying by heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2201/00—Pretreatment
- F23G2201/60—Separating
- F23G2201/603—Separating recyclable material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2201/00—Pretreatment
- F23G2201/80—Shredding
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2202/00—Combustion
- F23G2202/30—Combustion in a pressurised chamber
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2205/00—Waste feed arrangements
- F23G2205/12—Waste feed arrangements using conveyors
- F23G2205/121—Screw conveyor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2205/00—Waste feed arrangements
- F23G2205/14—Waste feed arrangements using hopper or bin
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2205/00—Waste feed arrangements
- F23G2205/18—Waste feed arrangements using airlock systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2205/00—Waste feed arrangements
- F23G2205/20—Waste feed arrangements using airblast or pneumatic feeding
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2206/00—Waste heat recuperation
- F23G2206/20—Waste heat recuperation using the heat in association with another installation
- F23G2206/203—Waste heat recuperation using the heat in association with another installation with a power/heat generating installation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2900/00—Special features of, or arrangements for incinerators
- F23G2900/50214—Separating non combustible matters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/12—Heat utilisation in combustion or incineration of waste
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Energy (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Wood Science & Technology (AREA)
- Solid-Fuel Combustion (AREA)
- Incineration Of Waste (AREA)
Abstract
A system for burning biomass to produce hot gas includes a wood processing system (28), a combustor (14), a cyclone ash separator (16), a turbine (18), and a control system (136). An air bypass assembly controls a flow of bypass air (128) to combine with the combustion gas prior to feed of the combustion gas to the turbine (18).
Description
WO 98/46~9 . . PCT/US97/23647 D D~scription SYS TE~ FOR BU~N. TNG B IOM~S S
TO PRODUCE HOT ~A.
Technical Field This invention relates to the field o~
power plants and more specifically to a system ~or prducing hot gas to pwoer a trubine, or for a ~ossil booster or incinerator.
Backgrol~nd A~t Developing alternative sources of ~uel has become an increasing concern both environmentally and economically. Traditional ~ossil fuels are becoming rare and expensive.
Burning them, often has a negative impact on the environment.
In an ef~ort to solve the problems associated with traditonal fossil fuels, WO ~8/~ C9 . PCT/US97/23647 attention has been directed toward burning biomass to fuel a ~urbine system. Biomass, in the form of sawdust, has proven to be a viable option for fueling turbine systems.
A turbine system consists generally of a combustion chamber for burning fuel in the presence of compressed air provided by an air compressor gas generator, a turbine into which high pressure combustion gas flows, expands and produces power to drive the air compressor, and an electrical generator which is powered by the power turbine.
When designing a system to burn wood, several issues must be addressed. Wood combusts at a substantially higher temperature than traditional fossil ~uels. The life and ef~ectiveness of the turbine will be substantially af~ected by high temperatures and ash, a byproduct o~ burning wood. Further, the abrasiveness of sawdust and the combustion of sawdust must be considered when ~eeding the sawdust into the combustion chamber.
Several systems have been developed for burning wood to produce power. Typical of the CA 022~8~79 l999-Ol-l~
W098/46869 . PCT~S97/23647 art are those devices disclosed in the following U.S. Patents:
Pat. No. Inventor(~) Issue Date 2,735,266 G.H. Atherton Feb. 21, 1956 4,409,786 Hamrick et al. Oct. 18, 1983 5,341,637 Hamrick Aug. 30, 1954 The '266 patent teaches a portable, self contained power plant for converting wood waste to electrical energy. A chamber is utilized to burn and pyrolize wood on a grate to form combustible products which are in turn injected into a second combustion chamber for complete combustion. The system generates a relatively low amount of energy due to low wood burning rates inherent with burning on a grate or pile.
Further, the system does not provide a suf~icient means for removing ash from the combustion gas. Also, a control system is not provided ~or controlling various aspects o~ the system during operation thereo~.
The '786 and '637 patents teach wood burning systems for fueling a turbine. Each system is designed to generate a large amount of energy. The '786 patent does not teach a CA 022~8579 Isgg-ol-l~
W098/46869 . . PCT~S97J23647 control system suf~icient for commercial operation o~ the system. The systems taught in both patents teach combustors wherein the biomass is fed into the combustor ~rom the top or proximate the top. Combustion o~ wood particles is inef~icient with this con~iguration because the larger particles move out of the combustion zone, due to gravity, be~ore they entirely combust. Further, the feediny system disclosed in both patents is not sufficient ~or commercial application.
Moreover, with the design of the '637 combustion chamber, slag is prone to collect on the walls of the chamber. Also, the combustion 15- chamber and cyclone filter design o~ the '637 patent tend to ~oster pressure drops. Further, the control system disclosed in the '637 patent does not provide ~or environmental concerns.
Therefore, it is an object of the present invention to provide a system ~or burning biomass to produce hot gas which includes a ~eeding system such that the system can be used commercially.
CA 022~8~79 Issg-ol-l~
W098/46869 . PCT~S97/23647 It is another object of the present invention to provide a system for burning biomass which includes a more efficient and smaller combustor and cyclone ~ilter.
It is yet another object of the present invention to provide such a system which combusts the biomass more efficiently.
Moreover, it is an object of the present invention to provide a system for burning biomass to produce hot gas which includes a control system for monitoring and controlling environmentally damaging gas within the exhaust gas.
Summary Other objects and advantages will be accomplished by the present invention which provides a system for burning biomass to produce hot gas for powering a turbine. The system o~ the present invention includes a wood processing system, a combustor, a cyclone ash separator, a gas generator, a turbine and a control system. The wood processing system --CA 022~8~79 lgss-ol-l~
W098/46869 . PCT~S97~3647 serves to process, dry and prepare the biomass for injection into the combustor. The biomass is injected into the bottom of the combustor.
Combustion o~ the biomass takes place in the combustor. The resultant combustion gas enters the cyclone ash separator ~or removal o~ ash from the combustion gas. The combustion gas exits the cyclone ash separator via a duct. An air bypass assembly permits the injection of bypass air into the stream of the combustion gas at t~e exit of the cyclone. The combustion gas and bypass air enter the turbine, where they expand to power the turbine which drives an electrical generator.
Rrief Description of the Drawinas The above mentioned features of the invention will become more clearly understood from the following detailed description o~ the invention read together with the drawings in which:
Figure 1 illustrates the biomass burning system of the present invention;
CA 022~8~79 1999-01-1~
W098/46869 . PCT~S97/23647 Figure 2 illustrates the wood processing system of the present invention;
Figure 3 illustrates an alternate embodiment o~ the sawdust preparation system of the present invention;
Figure 4 illustrates an enlarged view of the combustor and cyclone;
Figure 4A illustrates an in~ector region for a combustor to accommodate the use of very fine particulate fuel.
Figure 5 is a top view of the vanes and vane actuator at the lower end of the combustor;
Figure ~ is an alternate embodiment of the air bypass assembly;
Figure 7 is a block diagram of the control system for the system for burning biomass of the present invention; and, Figure 8 illustrates the major CCP input and output signals and controller functions.
Description of the Preferred Embodiments CA 022~8~79 1999-01-1~
WO ~8/~68~9 - . - PC~T/IJS97/23647 A system ~or burning biomass to produce hot gas to power a turbine incorporating varlous features of the present invention is illustrated generally at 10 in Figure 1. It will be noted that although a system for providing hot gas to power a turbine is described herein, it is not intended to limit the system to this particular use and can be utilized as a hot air source ~or a fossil power plant booster or an incinerator.
The system for burning biomass 10 is designed to provide an improved wood processing system. Further, the system provides an improved manner ~or injecting the biomass into the combustor 14. Moreover, an extensive control system 22, shown in Figure 7, is provided ~or monitoring and controlling various aspects o~ the system 10, as well as exhausts and byproducts o~ the system 10.
The system for burning biomass 10 of the present invention generally includes a biomass (typically wood sawdust~ processing system 12 (shown in Figure 2), a combustor 14, a cyclone CA 022~8~79 l999-Ol-l~
W0~8/4686~ - . PCT~S97/23617 .
ash separator 16, a gas generator 18 (including both a gas generator turbine 20 and a compressor 21), a power turbine 19, an electrical generator 17 (shown in Figure 1), and a control system 22 (shown in Figure 7).
The power turbine 19 is coupled to the generator 17 through a gear box 123 and a brake 125.
Referring to Figure 2, the wood processing system 12 includes a reclaiming system 26, a sawdust preparation system 28, a storage unit 30 and a pressurized lock vessel assembly 32.
The reclaiming system 26 includes a dump hopper 34 into which the sawdust is dumped. The sawdust is fed ~rom the dump hopper 34, by a reclaimer 35, onto a drag conveyor system 36 including a first 130, second 131 and third drag conveyor 132. The first conveyor 130 includes a magnet 38 at its terminal end ~or removing iron and other ferrous metals ~rom the sawdust. The second and third conveyors 131, 132 are used to divert biomass into aspirator bins 40A, 40B. In the pre~erred embodiment, _ CA 022~8~79 1999-01-15 W098/46869 - . PCT~S97/23647 the drag conveyor system 36 is designed to convey a maximum of ten tons per hour. The drag conveyor system 36 feeds the sawdust into a destoner or aspirator 40 (A and B) which removes rocks, bark, bottles and other remaining debris, From the destoner/aspirator 40, the sawdust is fed pneumatically into the sawdust preparation system 28. The sawdust preparation system 28 consists of two or more parallel paths to obtain the desired flow rate of biomass ~uel.
In the preferred embodiment, the (e.g.,sawdust) biomass preparation system 28 includes at least one air swept pulverizer 42A
(and preferably a second air swept pulverizer 42B) which serves to pulverize, dry and classify the sawdust in one efficient operation. The air swept pulverizers 42A, 42B
can be operated in an ambient pressure mode or high pressurized mode. The ambient pressure mode has ~he advantage of being able to blend differen~ types o~ ~uels with di~ferent moisture content prior to combustion. The high CA 022~8~79 Isgg-ol-l~
W098/46869 - . PCT~S97/2~647 pressurized mode has the advantage of processing only wet sawdust outside o~ the combustor thereby eliminating the potential explosion problem. Additionally, the process directs to the combustor all wood fuel ingredients including the wood alcohol vapors lost in the unpressurized system. In the wood processing system 12 depicted in Figure 2, two air swept pulverizers 42A, 42B are utilized and they are operated in the ambient pressure mode.
The sawdust enters the air swept pulverizers 42 at approximately ~orty-~ive weight percent water in a ~luidized air stream from the aspirators 40A, 40~3. The sawdust is dried in the air swept pulverizers 42 to approximately 20 weight percent water. In the preferred embodiment, turbine exhaust air ~rom the system lO is pulled through the pulverizers 42 to dry the biomass and each air swept pulverizer 42 pulverizes and dries 9,300 pounds per hour at 300 horsepower using 13,940 (ACFM) actual cubic ~eet per minute o~ 600~F turbine exhaust air.
Drying air dampers 61 ~eed drying air into the W098/46869 . - PCT~S97/23647 pulverizers 42. Each air swept pulverizer 42 processes 9,300 pounds per hour o~ sawdust at 45 weight percent moisture to approximately 6,480 pounds per hour of wood fuel at 20 weight percent moisture. The preferred air swept pulverizer 42 is a Jacobson air swept pulverizer, model number 48-H.
Radial materials fans 43A, 43B are used to pull drying air (47) and biomass fuel which is being dried in the pulverizers 42A, 42B through the drying system and forces the air through cyclones 44A, 44B. The fluidized transfer process greatly increases the efficiency o~ the drying process. An elevated loop in the ~luidized transport ducts 41A, 41B totally eliminates the possibility of introducing any high mass objects such as stones and metals into the biomass fuel pulverizers 42A, 42B.
Cyclones 44A, 44B are in communication with each of the air swept pulverizers 42A, 42B, and the biomass fuel from the pulverizers 42A, 42B is fed into the cyclones 44A, 44B by the materials fans 43A, 43B. The lower end of CA 022~8~79 l999-Ol-l~
W098/46869 - . PCT~S97/23647 the cyclones 44A, 44B define rotary feeders 46A, 46B which pass the biomass into a pneumatic conveyor 48.
The pneumatic conveyor 48 moves the biomass into the top of a storage cyclone 30.
The biomass is discharged from the bottom of the cyclone 30 into a live bin 52. Inclined drag conveyors could also be used in the place of the pneumatic conveyor to fill the live bin 52. The live bin 52 has a reversing cross auger and eight feed augers 51 that will move the fuel dust to one of two lock vessels 56A, 56B .
The pressurized fuel dust ejector assembly 32 includes one or two pressurized lock vessels 56A, 56B which communicate in a parallel manner to the charging vessel 57. Each lock vessel 56A, 56B can be cross-charged with compressed air from the other and topped off with mechanical compressed air before it is connected to the charging vessel 56. This eliminates pressure surge in the feed system and pressure surges in the gas compressor CA 022~8~79 I999-ol-l~
W098/46869 . PCT~S97/23647 system. Again the charge vessels are repressurized before ~eeding the biomass into the charging vessel 57. An auger 58 at the bottom o~ the charging vessel 57 typically meters out biomass at 1-3.54 pounds per second into the pressurized combustor 1~. Compressed air ~rom the compressor 21 is input to a high temperature and pressure blower 59 which is used to boost the ~uel dust conveying air which discharge~ into the combustor 14. Plant compressed air is used to activate rubber vibrator jets 49 on the side o~ the lock vessels 56A, 56B and the walls o~ the charge vessel 57. These jets ~luidize the ~uel dust so i~ does not bridge or plug the holes in the ejector lock vessels 56A, 56B and/or the charge vessel 57. The charge vessel 57 also has a centerline-mounted rotating mechanical and air jet brldge breaker 50 that keeps the ~uel dust in a ~luidized state so that it moves to the discharge auger 58 without bridging or rat holing in the charge vessel.
CA 022~8~79 1999-01-1~
WO ~8/461~6g . . PCT/I~S97/23647 , In an alternate e~bodiment, the lock vessels 56A, 56B and the charge vessel 57 are equipped with internal rotating vessels and a fixed bridge breaking screw auger to move the fuel out o~ the lock vessels into the charge vessel 57 and to break the bridge in the charge vessel and move the fuel dust through a metering screw so that it can be pneumatically injected into the combustor.
The wood processing system 12 further includes a manually fillable receptacle 60 positioned at the ~ront end of the pneumatic conveyor 48. The receptacle 60 provides a location for manually loading fuel dust or additives to the system. A second receptacle (not shown) can be positioned at the augers 51 as a convenient location to add additives when such are used to control the ash problem related to burning sawdust.
Pneumatically feeding of biomass (e.g., sawdust) from the aspirator bins 40A, 40B and metering augers to the pulverizers 42A, 42B , and pneumatically conveying the biomass fuel CA 022~8~79 l999-Ol-l~
WO 98M~ 'g ~ . PCT/US97/~3647 dust to the live bin 52 with materials fan 45 reduces the temperature o~ the drying air ~rom the turbine to 250~ or less eliminating the possibility of explosion o~ fuel dust in the pulverizers, their cyclones 44A, 44B, the live bin fan 45 and the live bin cyclone 30. The dust discharged ~rom the pulverizer cyclones 44A, 44B and live bin cyclone 30 is recycled to a bag house 47 through a rotary lock 46 back into the conveyor line 48 by ~an 43.
In an alternate embodiment, shown in Figure 3, the sawdust preparation system 28 includes the use of a pressurized air swept pulverizer system 162. In the embodiment shown, two air swept pulverizer systems 162 are utilized in a parallel manner (as in Figure 2) to ~eed into one high pressure and high temperature cyclone 171. It will be noted that one or more than one air swept pulverizer system 162 can be utilized. Each air swept pulverizer system 162 includes a biomass surge hopper 163, a ~irst isolation valve 164, a lock hopper 165, a second isolation valve 166, a CA 022~8~79 l999-Ol-l~
WO~/4~9 - . PCT~S97/23647 charge hopper 167, a metering screw 168, an air swept pulverizer ~eed hopper 169 and an air swept pulverizer 170. The biomass surge hopper 163 receives the processed sawdust ~rom the destoner or aspirator gO (see Figure 2). The sawdust moves through the ~irst isolation valve 164 and into the lock hopper 165 where the sawdust is pressurized and raised in temperature. In the preferred embodiment, the sawdust is pressurized to 125 psi and brought to a temperature o~ 150~F. The sawdust moves through the second isolation valve 166 into the charge hopper 167. In the pre~erred embodiment, the sawdust is maintained at the same pressure and brought up to 200~F. The metering screw 168 meters the sawdust into the air swept pulverizer ~eed hopper 169 which ~eeds the sawdust into the air swept pulverizer 110 a~ a rate o~ 5 tons/hour at 45 weight percent water. The sawdust is dried and pulverized in the air swept pulverizer 170.
Pre~erably, the sawdust is dried with hot air ~rom the compressor 21 (see Figure 1). In the CA 02258579 l999-Ol-lS
.W098/46869 . PCT~S97/23647 preferred embodiment, ducts 197, 198 are in communication with the combustor duct 25 to feed air into the pulverizers 170.
From the air swept pulverizer system(s) 162, the wood fuel is fed into a high pressure, high temperature cyclone 171, where the wood fuel 152 is separated from the gas.
Pre~erably, the cyclone 171 is held a~ 350~F
and 125.5 psi. The high temperature air is exhausted through the top of the cyclone 171 and is injected into the combustor 14 via the port 95 to increase power and BTU input. The wood fuel 152 exits through the lower end of the cyclone 171 through a high temperature rotary air lock 172 and enters a pneumatic feed line 173. Primary air 150 from a conveying air line 174 i5 fed into the rotary air lock 172 to mix with the wood fuel 152. In the pre~erred embodiment, the rotary air lock 172 is held at 605~F and a pressure dif~erential o~ 0.5 psi and ~he conveying air line 174 is at 126.5 psi and delivers air into the rotary air lock 172 a~ a temperature of 605~F and a rate o~ 2-4 CA 022~8~79 1999-01-1~
W098/46869 . PCT~S97123647 pounds/sec. The wood fuel 152 and primary air 150 are fed into the bottom of the combustor 14 via the pneumatic air line 173. In the preferred embodiment, the air 150 and wood fuel 152 mixture is delivered at a temperature of 500~F and a pressure of 126 psi; the air 150 is delivered at a rate of 8 pounds/second and the wood fuel 152 at a rate of 1-5 pounds /second at 20 weight percent water.
In the preferred embodiment, the primary air 150 is fed from the air compressor 21 which delivers the air at 600~F and a pressure of 125 psi. A booster fan 175 mounted in a pressure vessel 176 is utilized to boost the pressure and temperature of the primary air 150 before it enters the conveying air line 174.
It is advantageous to use the pressurized alr swept pulverizer system because there is no dry fuel handling. This decreases the potential fire problem, and all volatile organic compounds are burned. Further, this system offers better fuel efficiency and emissions control and added power. Moreover, CA 022~8~79 Issg-ol-l~
W098/46869 . . PCT~S97/236~7 less capital equipment is required to process the sawdust.
The combustor 14, shown clearly in Figure 4, is a pressure balanced bottom ~uel feed combustor. The combustor 14 includes an outer shell 66, a combustor lining 68 defining a network of openings 71 and annular slots 70, an annulus 72 between the outer shell 66 and the combustor lining 68, a bottom fuel injector 74, a gas burner 78, and a commercial gas burner controller 190. The outer shell 66 defines a port 95 at a lower end thereo~. During operation o~ the system 10, the port 95 receives secondary and tertiary air 128 from the air compressor 21, which i9 powered by the gas generator turbine 20. A check valve 24 (~igure 1) is included in the air vent 25 to the combustor 14 at port 95 to prevent back ~10w from the combustor 14 such that damage to the compressor 21 is prevented. Also, a pressure relie~ valve 6~ i8 in communication with the duct 25 ~or relieving pressure in the system. Further, an alternate embodiment CA 022~8~79 l999-Ol-l~
W098/46869 ~ PCT~S97/23647 , includes a steam injector 134 to inject steam into the tertiary air 128 of the annulus 72 of the combustor 14 and/or the annulus 98 of the cyclone 16. Steam is injected to boost turbine power after reaching 90~ of achievable power by using wood fuel only. In the preferred embodiment, the outer shell 66 is fabricated from 0.5 in. thick carbon steel or the equivalent and the inside of the outer shell 66 is insulated with 3" thick fiber~raxTM
insulation retained by a 0.078" stainless steel floating liner.
The bottom fuel injector 74 injects the wood fuel 152 from the wood processing system 12 into the bottom of the combustor 14. The fuel is metered into the pneumatic line entering the fuel injector 74 by the metering screw 58. Bottom injection of fuel into the combustor 14 increases residence time of the fuel in the combustor 14 and reduces the required energy for injection. Bottom injection also prevents accumulation of unburned, ashes and slag inside the combustor CA 022~8~79 l999-Ol-l~
W098/46869 . . PCT~S97/23647 14. In the preferred embodiment, the combustion zone at the orifice of the fuel injector 74 is lined with a refractory casting of Andalucast LCV (FSS-1151) cured to 650~F.
The lower end of the combustor 14 is configured to promote thorough burning of the wood fuel 152 fed into the combustor 14.
Generally, the lower end of the combustor 14 includes a refractory cone 80 and a secondary air flow controller 178, shown in Figure 5, for controlling the air 128 flowing from the combustor annulus 72 into the re~ractory cone section 153. The refractory cone 80 serves to accumulate and radiate heat to stabilize initial combustion. In the preferred embodiment, the control of the secondary air flow 128 is accomplished by a plurality of movable vanes 179 which are controlled by a vane actuator 180, shown generally in Figure 4.
For applications that may involve the use of very fine particulate (dust) fuel, it may be necessary to have means for initiating combustions. An embodiment of such a fuel CA 022~8~79 I999-ol-l~
~098/~6869 ~ . PCT~S97/23647 injector 74 ' iS illustrated in Figure 4A. In this embodiment, a liquid fuel line 75 is disposed within the lower end of the combustor 14 to convey fuel to a nozzle 76 positioned proximate the cone 80. This fuel line 75 is protected from extreme the incoming regular ~uel 152 with a barrier 77. The liquid fuel is ignited in any normal manner at the nozzle 76 to raise the temperature of the dust of regular ~uel to initial combustion temperature.
Thereafter, the liquid ~uel ~low can be terminated.
A top view of the vanes 179 is shown in Figure 5. The vanes 179 encircle the exit of the fuel injector 74. Each of the vanes 179 pivots relative to one end such that the vanes 179 can be maneuvered to control air flow therethrough. As shown in Figure 5, the vanes are positioned in a fully open position thereby permittlng a maximum air flow. Controlling the amount of secondary air 128 flowing into the lower end o~ the combustor 14 controls both the secondary air 128 to wood fuel 152 ratio and CA 022~8~79 l999-Ol-l~
W098/46~G~ ~ . PCT~S97/23647 the flame temperature in the re~ractory section 153 of the combustor and promotes swirling of the wood fuel 152 ~or a more thorough combustion o~ the wood ~uel 152. The degree of opening between the vanes 179 is achieved with the actuator 180 which either draws the vanes closer or separates them via the connecting linkage 181.
The combustor ~iner 68 defines a plurality o~ spaced annular slots 70, as shown in Figure 4. The annular slots 70 permit cooling-dilution air 129 ~lowing in the annulus 72 to enter into the combustion zone 122 ~or supporting combustion throughout the combustor 14 and controlling the ~lame and gas temperature. In the preferred embodiment, the combustor liner 68 is manufactured from 0.125 in. thick INCONEL 625, 309 SST or 310 SST.
Cooling-dilution air 129 circulates within the annulus 72 to cool the combustor llner 68.
Pre~erably, the combustor liner 68 is cooled to below the ash slagging temperature such that .
MISSING UPON TIME OF PUBLICATION
CA 022~8~79 lsgg-ol-l~
~0 98/46869 . . - PCT/US97/23647 bypass assembly 104 are provided proximate the exit of the cyclone ash separator 16. In the preferred embodiment, the outer shell 94 oi~ the cyclone 16 ls fabricated from carbon steel or the equivalent. The annulus 98 o:E the cyclone 16 is in communication with the annulus 90 of the communication pipe 84 which ls in communication with the annulus 72 of the combustor 14. Cooling-dilution air 129 is circulated in the annulus 98 between the outer shell 94 and the cyclone liner 96 from the combustor annulus 72. The cooling-dilution air 129 flows around the cyclone liner 96 to cool the cyclone liner 96 and keep the ~iner 96 below slagging temperature. Further, the circulating air serves to cool the outside shell 94 of~ the cyclone 16 to reduce thermal losses.
The ash collector 100 is located at the lower end of the cyclone liner 96 and defines two ash lock hoppers 106, 108 for receiving and holding the ash collected. Each ash lock hopper 106, 108 defines a discharging valve 109 CA 022~8~79 l9ss-ol-l~
W098/4~869 - . PCT~S97/23647 the generator break 125 and emergency shutdown button in the control room. The relief valves 127 are operated by the system pressure.
The air bypass asse~mbly 104 permits and controls the flow of air 128 (air flowing in the annulus 98 of the cyclone 16) combining with the cleaned combustion gas 126 as the gas 126 exits the cyclone 16 through the duct 110.
In the embodiment shown in Figure 4, the air bypass assembly 104 includes a fixed sleeve 182, a control sleeve 185 and an outlet pipe 184. The fixed sleeve 182 is de~ined by the first end of the duct 110 exiting the cyclone 16. The fixed sleeve 182 encircles the outlet pipe 184 in a m~nne~ such that an annular space 186 is defined therebetween. The annular space 186 is unobstructed at the upper end thereof.
The ~ixed sleeve 182 supports the lower end o~
the outlet pipe 184 such that it is retained within the fixed sleeve 182. Further, the fixed sleeve 182 defines a plurality of openings 183 at an upper portion thereof, as shown in Figure 1. The control s~eeve 185 is CA 022~8~79 lggg-ol-l~
W098/46869 ~ . PCT~S97123647 , annularly received by an outer surface of the fixed sleeve 182 proximate the plurality of openings 183 and defines a plurality of openings 187 which correspond to the openings 183 defined by the fixed sleeve 182, as shown in Figure 1. The control sleeve 185 rotates to control the flow of air 128 flowing from the annulus 98 of the cyclone 16 through the upper portion of the annular space 186 dei~ined between the fixed sleeve 182 and the outlet pipe 184. This air 128 combines with the combustion gas 126 exiting the upper end of the outlet pipe 184. In the preferred embodiment, the control sleeve 185 rotates in a limited manner, in one direction to fully block the openings 183 of the fixed sleeve 182 and in the opposing direction to reveal partially or fully the openings 183 of the ~ixed sleeve 182 there~y controlling the flow rate of the tertiary air or cooling-dilution air 129. The lower end of outlet pipe 184 defines a plurality of vents 188. Air ~lowing in the lower portion of the annular space 18 6 serves CA 022~8~79 lgss-ol-l~
W098/46869 . PCT~S97/23647 to cool the outlet pipe 184 and exits through the vents 188 into the entrance of the outlet pipe 184 to combine with the cleaned combustion gas 126.
In an alternate embodiment shown in Figure 6, the air bypass assembly 104 includes a casing 112 sealed around the first end of the duct 110 and a pressure controlled bypass flow valve 114. The first end o~ the duct 110 de~ines a plurality o~ openings 116 open to the casing 112. When the valve 114 is opened, air ~rom the cyclone annulus 98 flows into the casing 112, through the plurality o~ openings 116 and into the duct 110 and combines with the cleaned combustion gas 126. In the pre~erred embodiment, the bypass ~low valve 114 is manufactured ~rom SST 309 or an equivalent ~aterial.
The flame temperature and cyclone exit air temperature are monitored and controlled with excess air by modulating the bypass flow. The bypassed air 128 is directed into the cyclone exit vortex to decrease cyclone pressure loss CA 022~8~79 lsgg-ol-l~
W098/46869 - . PCT~S97/23647 and to increase cyclone e~iciency during operation o~ the system.
In an alternate em~odiment (see Figure 1), a steam injector 118 is in communication with the duct llO to inject steam into the stream o~
cleaned combustion gas 126 and bypassed air for added power. In an alternate embodiment, steam injectors 134 (see Figure 4) are utilized to inject steam into the secondary air 128 at the lower end o~ the combustor 14 and the lower end o~ the cyclone 16.
To begin operation o~ the system 10, the gas generator 18 is rotated at low speed with a hydraulic starter (not shown) to create a gentle dra~t and purge the system 10. Natural gas, oil or LPG is injected into the bottom o~
the combustor 14, through the starter ~uel inlet or gas burner 78, and ignited by a high temperature electrical spark to warm the combustor 14 and cyclone 16 and preheat the re~ractory cone 80. During initial start up and idle the gas burner 78 is utilized and is controlled via the commercial gas burner CA 022~8~79 1999-01-1~
WO 98/46869 - . PCT/US97/Z3647 .
controller 190 which includes a gas pressure control 192 and an air flow control 194.
The gas generator 18 is accelerated by the starter engine, and sawdust fuel 152 injection is started. After the sawdust fuel 152 i8 ignited and the speed of the gas generator turbine 20 is increased by a combination of energy input from the starter engine and the progressively increased combustion rate, the natural gas ~uel/oil is turned off. When the gas generator 18 reaches a self-sustaining energy balance speed, the starter engine is turned of~. Pre~erably, the sawdust fuel feed rate i8 3.5 lb/sec with 2 - 4 lb/sec primary air.
Secondary and tertiary air 128 are supplied from the compressor 21 and function to support combustion and control ~lame and gas temperature. The air 128 enters the combustor via the port 95 at the bottom o~ the combustor 14. In one embodiment, the air enters the port 95 at a rate o~ 121.5 lb/sec, a temperature of 600~F and a pressure of 125 psi with a density CA 022~8~79 I999-Ol-l~
W098/46869 . PCT~S97/23647 o~ 0.318 ft3/sec. The secondary air 128 ~lows through the vanes 179 at the lower end of the combustor 14 and enters the re~ractory section 153. The secondary air 128 flowing through the vanes 179 serves two main ~unctions: to swirl the wood ~uel 152 as it feeds into the re~ractory section 153; and to control the flame temperature in the refractory section 153. The vanes 179 are con~igured such that as lo the air/wood ~uel mixture enters the re~ractory section 153 it establishes a swirling action such that the wood fuel 152 is retained within the re~ractory section 153 for an extended period to encourage more thorough heating of the wood fuel 152, ultimately encouraging combustion o~ all wood ~uel 152. The conditions in the re~ractory section 153 are below stoichiometric conditions such that complete combustion does not take place in the re~ractory section 153.
The majority of the tertiary air 130 enters the combustion zone 154 just above the refractory 80 through a network o~ holes and/or CA 022~8~79 lgss-ol-l~
WO 98/46869 ~ . PCI~/US97/23647 slots 71 dei~ined by the combustor liner 68 to complete combustlon in a super stoichiometric condition. The amount o~ air :Eed into the combustion zone 122 is such that the oxygen content is above stoichiometry. The surface temperatures inside the combustor liner 68 are about 1400~F maximum due to cooling by the cooling-dilution air 129 which is at approximately 640~F. Surf~ace temperatures of the outside of the combustor liner 68 are approximately 910~F while the insulated outer wall of~ the outer shell 66 is about 269~F. The resulting outside ambient air is about 100~F.
The primary air 150 for injection with the wood :Euel 152 comes directly ~rom the compressor 21. When utilizing the sawdust preparation system shown in Figure 2, the air iB fed through a booster f~an. The sawdust i~uel 152 enters ~rom the bottom o~ the pressurized charge vessel assembly 32 and is carried by the primary air 150 to the bottom oi~ the combustor 14 where it is injected. When utilizing the sawdust preparation system depicted in Figure CA 022~8~79 l999-Ol-l~
W0~8/4~86~ - . PCT~S97/23647 , 3, the booster ~an 175, mounted in a pressure vessel 176, is utilized to boost the pressure and temperature of the primary air 150 be~ore it is ultimately delivered to the bottom o~ the combustor 14.
Combustion temperatures inside the re~ractory section 153 at the bottom o~ the combustor 14 reach approximately 2200~F (~or a short period o~ time, e.g., less that 1 sec.) and decrease along the combustor as the cooling-dilution air 129 ~lows into the combustion zones through the combustor annular slots 70. The cooling of the inner wall o~ the combustor liner 68 by the cooling-dilution air 129 ~low prevents slag ~ormation and residue inside the combustor liner wall. The temperature o~ the combustion gas cools to 1600~F maximum as it turns into the communication pipe 84 joining the combustor 14 and the cyclone 16.
Particulates are separated ~rom the combustion gas 125 in the cyclone ash separator 16 and are ultimately collected at the bottom CA 022~8~79 1999-01-1~
W098/46869 - . - PCT~S97/23647 .
in the second ash lock hopper 108. Clean combustion gas 126 exits at the top of the cyclone 16 at a maximum temperature of 1580~F, at 70 lb/sec and at 122 psi. As it exits, the clean combustion gas 126 is mixed with diverted air 128 from the air bypass assembly 104 and then is routed to the turbine 20 via the duct 110, at a pressure o~ approximately 122 psi and a temperature of 1350~F.
The use of the bypass air allows the combustor volume to be reduced. The lower air-gas flow rate through the co~bustor 14 and the cyclone 16 decreases ash carry over and allows the design o~ a more e~icient cyclone 16.
This ~eature reduces the ash grains per cubic foot in the turbine exhaust by 50%.
The gas generator 18 utilized in the system 10 has a split shaft to allow the gas generator turbine 20 and power turbine 19 to rotate at di~ferent revolutions per minute. In the pre~erred embodiment, the gas generator 18 is a modi~ied commercial gas turbine with a special center section and automatic check CA 022~8~79 l999-Ol-l~
W098/~68C~ - . PCT~S97/23647 valves 121 to allow off-board firing without blowback. These automatic check valves 121 reduce the pressure drop between the compressor discharge and the turbine inlet, as well as reducing compressor air back-pressure for easy start of the gas generator.
Upon entering the gas generator turbine 20, the combustion gas 126 expands to produce work. The gas generator turbine 20 powers the air compressor 21 via a drive shaft. The power turbine 19 drives the electrical generator 17 which is linked to any suitable electrical power transmission line. The power in excess of that required to drive the biomass burning system 10 is supplied to the outside user.
There~ore, a load rejection device is not needed due to the internal use of electrical power in the biomass burning system 10 and specifically in the wood drying process and the use of a special brake between the turbine gear box 123 and generator 17. I~ the generator 17 should be disconnected ~rom the power grid or lose its field, the central control system 136 CA 022~8~79 1999-01-1~
W098/46869 . - PCT~S97/23647 would automatically stop the biomass fuel dust, open the pressure relief valves 127 and apply a caliper brake 125 to prevent a generator overspeed.
Steam is injected (as at 118) to boost turbine power a~ter reaching 90% of achievable power by using wood fuel only.
Re~erring to ~igure 7, the control system 22 includes a com~ustion control processor (CCP) 136 which is utilized to monitor and control the biomass burning system 10. The CCP
136 is a distributed process controller that regulates the combustion process and monitors the combustion gas 125 and cleaned combustion gas 126. In the pre~erred embodiment, the distributed process controller is a Bristol Babcock 3335 DPC. The purpose o~ the control system 22 is to monitor functions ~rom the biomass burning system 10, a generator 20-- instrument package (GIP) 140, a turbine instrument package (TIP) 138 and a continuous emissions monitor (CEM) 142, and to use these inputs to provide a safe and e~icient control CA 022~8~79 l999-Ol-l~
W098/468C9 . PCT~S97/23647 o~ the biomass burning system 10 and to instruct the speed tachometer 146 and power controller 148. In the preferred embodiment, the GIP is an Allen Bradley line synchronization module, the TIP is manu~actured by General Electric (model number 7LM1500 GD102), and the CEM is an EPI 410.
Figure 8 illustrates the major CCP input and output signals and controller ~unctions.
Each are labeled according to the various elements o~ the system.
The biomass burning process includes the wood processing and the combustion process.
Selected conditions within the wood processing system 12, the combustor 14, the cyclone 16 and the gas generator 18 are monitored by the CCP
136. Within the wood processing system 12, the temperature o~ the hot exhaust ~or drying and the dryer inlet and outlet air temperatures are monitored. Moisture monitors 63 are located throughout the wood processing system 12 to monitor the moisture o~ the wood ~uel 152 as it is processed ~or use.
CA 022~8~79 Issg-ol-l~
W098/46869 . PCT~S97/23647 In the combustor 14, the temperature of the combustion zone 122 is monitored, and pre~erably the first 154, second 156, fourth 158 and ~ifth zones 160 are individually monitored. Moreover, the temperature at the entrance of the first combustion zone 154 and the temperature at the exit of the first zone 154 are specifically monitored. ~n the preferred embodiment, the temperatures at these various locations are measured with high temperature thermocouples, type S (as at 211 ln Figure 4). The temperature o~ the combustor 122 liner walls is controlled by modulating the cyclone bypass valve 185 to flow the proper amount o~ cooling-dilution air 129 through the combustor cooling annulus 72. The position of the cyclone bypass vlave 185 is controlled by the CCP 136.
The temperature of the pneumatically ~ed ~uel 152, the temperature o~ the primary air 150 a~ter the cooler and a~ter water injection, and the temperature o~ the secondary air 128 CA 022~8~79 lsss-ol-l~
W098/46869 ~ . PCT~S97/23647 before and a~ter steam injection are monitored, pre~erably, wlth type K thermocouples.
Also, the mass flow, the ~uel ~eed rate and pressure in the injection line 173 are monitored. Pre~erably, the mass ~low rate is measured with a Kurz mass flow monitor. The injection line ~uel ~eed rate is measured with a pressure transmitter. The ~eed rate o~ ~uel is a ~unction o~ the revolutions per minute (RPM) of the injector screw. The pressure at the exit of the combustor 1~, the pressure across the pneumatic ~eed booster and the compressor 21 air ~low into the combustor 1 are monitored, pre~erably, with pressure transmitters. Further, the temperature o~ the combustion gas 125 entering the cyclone and the cleaned combustion gas 126 exiting the cyclone are monitored.
In the gas generator 18, the temperature o~ the gas entering and leaving the compressor 21, the temperature o~ the gas entering the gas generator turbine 20, the temperature o~ the gas leaving the power turbine 19, the ~low rate W098/46869 . PCT~S97/23647 o~ air flowing in the gas generator air vent 25 and the pressure at the exit of the compressor 2~ are also monitored with similar transducers Further, the gas generator speed and the power turbine speed are monitored and, in the preferred embodiment, the load of the turbine 19 is also monitored such that the control system 22 can maintain the turbine 19 at a constant speed with a variable load. a more rapid response is provided when both the speed and the load are monitored.
The generator instrument package (GIP) 140 and the turbine instrument package (TIP) 138 function as industrial systems maintaining the turbine 19 and generator 18 ~unctions and monitor certain aspects of the generator 18 and the turbine 19, respectively, such as vibration, lube oil pressure and temperature, power turbine and gas generator RPM, generator 20_ volts, amps etc. The GIP 140 and TIP 138 provide controls ~or shutting down the system when preestablished limits have been passed.
CA 022~8~79 l999-Ol-l~
W098/46869 PCT~S97/23647 The continuous emissions monitor ( CEMS ) 142 controls emissions, regulates combustion and provides environmental reporting.
Speci~ically, the continuous emissions monitor 142 monitors the level o~ carbon monoxide, particulates, and NOX in the turbine exhaust gas. The CEMS controls emlssions by monitoring the exhaust carbon monoxide level and regulating the combustor air via the CCP. The controls are implemented to control the level o~ CO when it exceeds EPA standards.
The in~ormation from the biomass burning system lO, the gas generator 18, the GIP 140, the TIP 138 and the CEMS 142 is utilized to instruct the speed and power controllers 146, 148 such that the biomass burning system 10 operates in a sa~e and e~icient manner.
Speci~ically, the CCP 136 uses a so~tware program to control the steam injector 118 at the exit of the cyclone 16, the steam injectors 134 at the combustor 14 and the cyclone 16 when utilized, the vane actuator 180 ~or controlling the ~low o~ the secondary air 128 into the CA 022~8~79 Issg-ol-l~
W098/46869 , , PCT~S97/23647 combustor 14, the fuel feed injector 74, ~he gas burner controller 190, the air bypass assembly 104 and the thermal relie~ valve, 102, The CCP 136 outputs a current which provides a pressure signal to the vane actuator 180. The air bypass assembly 104 is set according to the system power level. The thermal relief valve 102 is interlocked with the distributed process controller and is opened with a key switch electro-pneumatic system.
The speed of the power turbine 19 is controlled in one o~ two manners depending upon whether the system 10 is linked to an outside system or not. When the biomass burning system 10 is connected to the outside transmission line, the speed is controlled by the 60 cycle balance of the transmission line. However, when the system 10 is connected to an internal load, the speed of the power turbine 19 and the gas generator 18 are under the control o~ the combustion control processor 136. a mechanical speed governor is utilized as a control loop independent of the combustion control processor CA 022~8~79 l999-Ol-l~
~098/46869 . PCT~S97/23647 136 for controlling the speed of the gas generator 18 in the event of a control system 22 failure. The bypass valves 121 are opened and closed during the start cycle according to compressor RPM and compressor discharge pressure schedule, and closed and opened during the shut down process to prevent compressor stalls and surges. These valves 121 are controlled by the CCP 136.
From the foregoing description, it will be recognized by those skilled in the art that a system for burning biomass to produce hot gas offering advantages over the prior art has been provided. Speci~ically, the system for burning biomass provides an improved manner for injecting the wood fuel 152 or biomass into the combustor lg. Further, the control system includes an air bypass assembly 104 for iniecting air into the stream of the combustion gas 126 to control the combustion process. The use of the bypass assembly 104 permits the use of smaller cyclone 16, increases the efficiency of the cyclone filter and controls slagging and CA 02258579 l999-0l-l5 W098/46869 . . PCT~S97~3647 emissions. Also, a thermal relle~ valve 102 is included for rapid cooling of the gas generator turbine 20 and the combustor 14.
While a pre~erred embodiment has been shown and described, it will be understood that it is not intended to limit the disclosure, but rather it is intended to cover all modi~ications and alternate methods falling within the spirit and the scope o~ the invention as de~ined in the appended claims.
TO PRODUCE HOT ~A.
Technical Field This invention relates to the field o~
power plants and more specifically to a system ~or prducing hot gas to pwoer a trubine, or for a ~ossil booster or incinerator.
Backgrol~nd A~t Developing alternative sources of ~uel has become an increasing concern both environmentally and economically. Traditional ~ossil fuels are becoming rare and expensive.
Burning them, often has a negative impact on the environment.
In an ef~ort to solve the problems associated with traditonal fossil fuels, WO ~8/~ C9 . PCT/US97/23647 attention has been directed toward burning biomass to fuel a ~urbine system. Biomass, in the form of sawdust, has proven to be a viable option for fueling turbine systems.
A turbine system consists generally of a combustion chamber for burning fuel in the presence of compressed air provided by an air compressor gas generator, a turbine into which high pressure combustion gas flows, expands and produces power to drive the air compressor, and an electrical generator which is powered by the power turbine.
When designing a system to burn wood, several issues must be addressed. Wood combusts at a substantially higher temperature than traditional fossil ~uels. The life and ef~ectiveness of the turbine will be substantially af~ected by high temperatures and ash, a byproduct o~ burning wood. Further, the abrasiveness of sawdust and the combustion of sawdust must be considered when ~eeding the sawdust into the combustion chamber.
Several systems have been developed for burning wood to produce power. Typical of the CA 022~8~79 l999-Ol-l~
W098/46869 . PCT~S97/23647 art are those devices disclosed in the following U.S. Patents:
Pat. No. Inventor(~) Issue Date 2,735,266 G.H. Atherton Feb. 21, 1956 4,409,786 Hamrick et al. Oct. 18, 1983 5,341,637 Hamrick Aug. 30, 1954 The '266 patent teaches a portable, self contained power plant for converting wood waste to electrical energy. A chamber is utilized to burn and pyrolize wood on a grate to form combustible products which are in turn injected into a second combustion chamber for complete combustion. The system generates a relatively low amount of energy due to low wood burning rates inherent with burning on a grate or pile.
Further, the system does not provide a suf~icient means for removing ash from the combustion gas. Also, a control system is not provided ~or controlling various aspects o~ the system during operation thereo~.
The '786 and '637 patents teach wood burning systems for fueling a turbine. Each system is designed to generate a large amount of energy. The '786 patent does not teach a CA 022~8579 Isgg-ol-l~
W098/46869 . . PCT~S97J23647 control system suf~icient for commercial operation o~ the system. The systems taught in both patents teach combustors wherein the biomass is fed into the combustor ~rom the top or proximate the top. Combustion o~ wood particles is inef~icient with this con~iguration because the larger particles move out of the combustion zone, due to gravity, be~ore they entirely combust. Further, the feediny system disclosed in both patents is not sufficient ~or commercial application.
Moreover, with the design of the '637 combustion chamber, slag is prone to collect on the walls of the chamber. Also, the combustion 15- chamber and cyclone filter design o~ the '637 patent tend to ~oster pressure drops. Further, the control system disclosed in the '637 patent does not provide ~or environmental concerns.
Therefore, it is an object of the present invention to provide a system ~or burning biomass to produce hot gas which includes a ~eeding system such that the system can be used commercially.
CA 022~8~79 Issg-ol-l~
W098/46869 . PCT~S97/23647 It is another object of the present invention to provide a system for burning biomass which includes a more efficient and smaller combustor and cyclone ~ilter.
It is yet another object of the present invention to provide such a system which combusts the biomass more efficiently.
Moreover, it is an object of the present invention to provide a system for burning biomass to produce hot gas which includes a control system for monitoring and controlling environmentally damaging gas within the exhaust gas.
Summary Other objects and advantages will be accomplished by the present invention which provides a system for burning biomass to produce hot gas for powering a turbine. The system o~ the present invention includes a wood processing system, a combustor, a cyclone ash separator, a gas generator, a turbine and a control system. The wood processing system --CA 022~8~79 lgss-ol-l~
W098/46869 . PCT~S97~3647 serves to process, dry and prepare the biomass for injection into the combustor. The biomass is injected into the bottom of the combustor.
Combustion o~ the biomass takes place in the combustor. The resultant combustion gas enters the cyclone ash separator ~or removal o~ ash from the combustion gas. The combustion gas exits the cyclone ash separator via a duct. An air bypass assembly permits the injection of bypass air into the stream of the combustion gas at t~e exit of the cyclone. The combustion gas and bypass air enter the turbine, where they expand to power the turbine which drives an electrical generator.
Rrief Description of the Drawinas The above mentioned features of the invention will become more clearly understood from the following detailed description o~ the invention read together with the drawings in which:
Figure 1 illustrates the biomass burning system of the present invention;
CA 022~8~79 1999-01-1~
W098/46869 . PCT~S97/23647 Figure 2 illustrates the wood processing system of the present invention;
Figure 3 illustrates an alternate embodiment o~ the sawdust preparation system of the present invention;
Figure 4 illustrates an enlarged view of the combustor and cyclone;
Figure 4A illustrates an in~ector region for a combustor to accommodate the use of very fine particulate fuel.
Figure 5 is a top view of the vanes and vane actuator at the lower end of the combustor;
Figure ~ is an alternate embodiment of the air bypass assembly;
Figure 7 is a block diagram of the control system for the system for burning biomass of the present invention; and, Figure 8 illustrates the major CCP input and output signals and controller functions.
Description of the Preferred Embodiments CA 022~8~79 1999-01-1~
WO ~8/~68~9 - . - PC~T/IJS97/23647 A system ~or burning biomass to produce hot gas to power a turbine incorporating varlous features of the present invention is illustrated generally at 10 in Figure 1. It will be noted that although a system for providing hot gas to power a turbine is described herein, it is not intended to limit the system to this particular use and can be utilized as a hot air source ~or a fossil power plant booster or an incinerator.
The system for burning biomass 10 is designed to provide an improved wood processing system. Further, the system provides an improved manner ~or injecting the biomass into the combustor 14. Moreover, an extensive control system 22, shown in Figure 7, is provided ~or monitoring and controlling various aspects o~ the system 10, as well as exhausts and byproducts o~ the system 10.
The system for burning biomass 10 of the present invention generally includes a biomass (typically wood sawdust~ processing system 12 (shown in Figure 2), a combustor 14, a cyclone CA 022~8~79 l999-Ol-l~
W0~8/4686~ - . PCT~S97/23617 .
ash separator 16, a gas generator 18 (including both a gas generator turbine 20 and a compressor 21), a power turbine 19, an electrical generator 17 (shown in Figure 1), and a control system 22 (shown in Figure 7).
The power turbine 19 is coupled to the generator 17 through a gear box 123 and a brake 125.
Referring to Figure 2, the wood processing system 12 includes a reclaiming system 26, a sawdust preparation system 28, a storage unit 30 and a pressurized lock vessel assembly 32.
The reclaiming system 26 includes a dump hopper 34 into which the sawdust is dumped. The sawdust is fed ~rom the dump hopper 34, by a reclaimer 35, onto a drag conveyor system 36 including a first 130, second 131 and third drag conveyor 132. The first conveyor 130 includes a magnet 38 at its terminal end ~or removing iron and other ferrous metals ~rom the sawdust. The second and third conveyors 131, 132 are used to divert biomass into aspirator bins 40A, 40B. In the pre~erred embodiment, _ CA 022~8~79 1999-01-15 W098/46869 - . PCT~S97/23647 the drag conveyor system 36 is designed to convey a maximum of ten tons per hour. The drag conveyor system 36 feeds the sawdust into a destoner or aspirator 40 (A and B) which removes rocks, bark, bottles and other remaining debris, From the destoner/aspirator 40, the sawdust is fed pneumatically into the sawdust preparation system 28. The sawdust preparation system 28 consists of two or more parallel paths to obtain the desired flow rate of biomass ~uel.
In the preferred embodiment, the (e.g.,sawdust) biomass preparation system 28 includes at least one air swept pulverizer 42A
(and preferably a second air swept pulverizer 42B) which serves to pulverize, dry and classify the sawdust in one efficient operation. The air swept pulverizers 42A, 42B
can be operated in an ambient pressure mode or high pressurized mode. The ambient pressure mode has ~he advantage of being able to blend differen~ types o~ ~uels with di~ferent moisture content prior to combustion. The high CA 022~8~79 Isgg-ol-l~
W098/46869 - . PCT~S97/2~647 pressurized mode has the advantage of processing only wet sawdust outside o~ the combustor thereby eliminating the potential explosion problem. Additionally, the process directs to the combustor all wood fuel ingredients including the wood alcohol vapors lost in the unpressurized system. In the wood processing system 12 depicted in Figure 2, two air swept pulverizers 42A, 42B are utilized and they are operated in the ambient pressure mode.
The sawdust enters the air swept pulverizers 42 at approximately ~orty-~ive weight percent water in a ~luidized air stream from the aspirators 40A, 40~3. The sawdust is dried in the air swept pulverizers 42 to approximately 20 weight percent water. In the preferred embodiment, turbine exhaust air ~rom the system lO is pulled through the pulverizers 42 to dry the biomass and each air swept pulverizer 42 pulverizes and dries 9,300 pounds per hour at 300 horsepower using 13,940 (ACFM) actual cubic ~eet per minute o~ 600~F turbine exhaust air.
Drying air dampers 61 ~eed drying air into the W098/46869 . - PCT~S97/23647 pulverizers 42. Each air swept pulverizer 42 processes 9,300 pounds per hour o~ sawdust at 45 weight percent moisture to approximately 6,480 pounds per hour of wood fuel at 20 weight percent moisture. The preferred air swept pulverizer 42 is a Jacobson air swept pulverizer, model number 48-H.
Radial materials fans 43A, 43B are used to pull drying air (47) and biomass fuel which is being dried in the pulverizers 42A, 42B through the drying system and forces the air through cyclones 44A, 44B. The fluidized transfer process greatly increases the efficiency o~ the drying process. An elevated loop in the ~luidized transport ducts 41A, 41B totally eliminates the possibility of introducing any high mass objects such as stones and metals into the biomass fuel pulverizers 42A, 42B.
Cyclones 44A, 44B are in communication with each of the air swept pulverizers 42A, 42B, and the biomass fuel from the pulverizers 42A, 42B is fed into the cyclones 44A, 44B by the materials fans 43A, 43B. The lower end of CA 022~8~79 l999-Ol-l~
W098/46869 - . PCT~S97/23647 the cyclones 44A, 44B define rotary feeders 46A, 46B which pass the biomass into a pneumatic conveyor 48.
The pneumatic conveyor 48 moves the biomass into the top of a storage cyclone 30.
The biomass is discharged from the bottom of the cyclone 30 into a live bin 52. Inclined drag conveyors could also be used in the place of the pneumatic conveyor to fill the live bin 52. The live bin 52 has a reversing cross auger and eight feed augers 51 that will move the fuel dust to one of two lock vessels 56A, 56B .
The pressurized fuel dust ejector assembly 32 includes one or two pressurized lock vessels 56A, 56B which communicate in a parallel manner to the charging vessel 57. Each lock vessel 56A, 56B can be cross-charged with compressed air from the other and topped off with mechanical compressed air before it is connected to the charging vessel 56. This eliminates pressure surge in the feed system and pressure surges in the gas compressor CA 022~8~79 I999-ol-l~
W098/46869 . PCT~S97/23647 system. Again the charge vessels are repressurized before ~eeding the biomass into the charging vessel 57. An auger 58 at the bottom o~ the charging vessel 57 typically meters out biomass at 1-3.54 pounds per second into the pressurized combustor 1~. Compressed air ~rom the compressor 21 is input to a high temperature and pressure blower 59 which is used to boost the ~uel dust conveying air which discharge~ into the combustor 14. Plant compressed air is used to activate rubber vibrator jets 49 on the side o~ the lock vessels 56A, 56B and the walls o~ the charge vessel 57. These jets ~luidize the ~uel dust so i~ does not bridge or plug the holes in the ejector lock vessels 56A, 56B and/or the charge vessel 57. The charge vessel 57 also has a centerline-mounted rotating mechanical and air jet brldge breaker 50 that keeps the ~uel dust in a ~luidized state so that it moves to the discharge auger 58 without bridging or rat holing in the charge vessel.
CA 022~8~79 1999-01-1~
WO ~8/461~6g . . PCT/I~S97/23647 , In an alternate e~bodiment, the lock vessels 56A, 56B and the charge vessel 57 are equipped with internal rotating vessels and a fixed bridge breaking screw auger to move the fuel out o~ the lock vessels into the charge vessel 57 and to break the bridge in the charge vessel and move the fuel dust through a metering screw so that it can be pneumatically injected into the combustor.
The wood processing system 12 further includes a manually fillable receptacle 60 positioned at the ~ront end of the pneumatic conveyor 48. The receptacle 60 provides a location for manually loading fuel dust or additives to the system. A second receptacle (not shown) can be positioned at the augers 51 as a convenient location to add additives when such are used to control the ash problem related to burning sawdust.
Pneumatically feeding of biomass (e.g., sawdust) from the aspirator bins 40A, 40B and metering augers to the pulverizers 42A, 42B , and pneumatically conveying the biomass fuel CA 022~8~79 l999-Ol-l~
WO 98M~ 'g ~ . PCT/US97/~3647 dust to the live bin 52 with materials fan 45 reduces the temperature o~ the drying air ~rom the turbine to 250~ or less eliminating the possibility of explosion o~ fuel dust in the pulverizers, their cyclones 44A, 44B, the live bin fan 45 and the live bin cyclone 30. The dust discharged ~rom the pulverizer cyclones 44A, 44B and live bin cyclone 30 is recycled to a bag house 47 through a rotary lock 46 back into the conveyor line 48 by ~an 43.
In an alternate embodiment, shown in Figure 3, the sawdust preparation system 28 includes the use of a pressurized air swept pulverizer system 162. In the embodiment shown, two air swept pulverizer systems 162 are utilized in a parallel manner (as in Figure 2) to ~eed into one high pressure and high temperature cyclone 171. It will be noted that one or more than one air swept pulverizer system 162 can be utilized. Each air swept pulverizer system 162 includes a biomass surge hopper 163, a ~irst isolation valve 164, a lock hopper 165, a second isolation valve 166, a CA 022~8~79 l999-Ol-l~
WO~/4~9 - . PCT~S97/23647 charge hopper 167, a metering screw 168, an air swept pulverizer ~eed hopper 169 and an air swept pulverizer 170. The biomass surge hopper 163 receives the processed sawdust ~rom the destoner or aspirator gO (see Figure 2). The sawdust moves through the ~irst isolation valve 164 and into the lock hopper 165 where the sawdust is pressurized and raised in temperature. In the preferred embodiment, the sawdust is pressurized to 125 psi and brought to a temperature o~ 150~F. The sawdust moves through the second isolation valve 166 into the charge hopper 167. In the pre~erred embodiment, the sawdust is maintained at the same pressure and brought up to 200~F. The metering screw 168 meters the sawdust into the air swept pulverizer ~eed hopper 169 which ~eeds the sawdust into the air swept pulverizer 110 a~ a rate o~ 5 tons/hour at 45 weight percent water. The sawdust is dried and pulverized in the air swept pulverizer 170.
Pre~erably, the sawdust is dried with hot air ~rom the compressor 21 (see Figure 1). In the CA 02258579 l999-Ol-lS
.W098/46869 . PCT~S97/23647 preferred embodiment, ducts 197, 198 are in communication with the combustor duct 25 to feed air into the pulverizers 170.
From the air swept pulverizer system(s) 162, the wood fuel is fed into a high pressure, high temperature cyclone 171, where the wood fuel 152 is separated from the gas.
Pre~erably, the cyclone 171 is held a~ 350~F
and 125.5 psi. The high temperature air is exhausted through the top of the cyclone 171 and is injected into the combustor 14 via the port 95 to increase power and BTU input. The wood fuel 152 exits through the lower end of the cyclone 171 through a high temperature rotary air lock 172 and enters a pneumatic feed line 173. Primary air 150 from a conveying air line 174 i5 fed into the rotary air lock 172 to mix with the wood fuel 152. In the pre~erred embodiment, the rotary air lock 172 is held at 605~F and a pressure dif~erential o~ 0.5 psi and ~he conveying air line 174 is at 126.5 psi and delivers air into the rotary air lock 172 a~ a temperature of 605~F and a rate o~ 2-4 CA 022~8~79 1999-01-1~
W098/46869 . PCT~S97123647 pounds/sec. The wood fuel 152 and primary air 150 are fed into the bottom of the combustor 14 via the pneumatic air line 173. In the preferred embodiment, the air 150 and wood fuel 152 mixture is delivered at a temperature of 500~F and a pressure of 126 psi; the air 150 is delivered at a rate of 8 pounds/second and the wood fuel 152 at a rate of 1-5 pounds /second at 20 weight percent water.
In the preferred embodiment, the primary air 150 is fed from the air compressor 21 which delivers the air at 600~F and a pressure of 125 psi. A booster fan 175 mounted in a pressure vessel 176 is utilized to boost the pressure and temperature of the primary air 150 before it enters the conveying air line 174.
It is advantageous to use the pressurized alr swept pulverizer system because there is no dry fuel handling. This decreases the potential fire problem, and all volatile organic compounds are burned. Further, this system offers better fuel efficiency and emissions control and added power. Moreover, CA 022~8~79 Issg-ol-l~
W098/46869 . . PCT~S97/236~7 less capital equipment is required to process the sawdust.
The combustor 14, shown clearly in Figure 4, is a pressure balanced bottom ~uel feed combustor. The combustor 14 includes an outer shell 66, a combustor lining 68 defining a network of openings 71 and annular slots 70, an annulus 72 between the outer shell 66 and the combustor lining 68, a bottom fuel injector 74, a gas burner 78, and a commercial gas burner controller 190. The outer shell 66 defines a port 95 at a lower end thereo~. During operation o~ the system 10, the port 95 receives secondary and tertiary air 128 from the air compressor 21, which i9 powered by the gas generator turbine 20. A check valve 24 (~igure 1) is included in the air vent 25 to the combustor 14 at port 95 to prevent back ~10w from the combustor 14 such that damage to the compressor 21 is prevented. Also, a pressure relie~ valve 6~ i8 in communication with the duct 25 ~or relieving pressure in the system. Further, an alternate embodiment CA 022~8~79 l999-Ol-l~
W098/46869 ~ PCT~S97/23647 , includes a steam injector 134 to inject steam into the tertiary air 128 of the annulus 72 of the combustor 14 and/or the annulus 98 of the cyclone 16. Steam is injected to boost turbine power after reaching 90~ of achievable power by using wood fuel only. In the preferred embodiment, the outer shell 66 is fabricated from 0.5 in. thick carbon steel or the equivalent and the inside of the outer shell 66 is insulated with 3" thick fiber~raxTM
insulation retained by a 0.078" stainless steel floating liner.
The bottom fuel injector 74 injects the wood fuel 152 from the wood processing system 12 into the bottom of the combustor 14. The fuel is metered into the pneumatic line entering the fuel injector 74 by the metering screw 58. Bottom injection of fuel into the combustor 14 increases residence time of the fuel in the combustor 14 and reduces the required energy for injection. Bottom injection also prevents accumulation of unburned, ashes and slag inside the combustor CA 022~8~79 l999-Ol-l~
W098/46869 . . PCT~S97/23647 14. In the preferred embodiment, the combustion zone at the orifice of the fuel injector 74 is lined with a refractory casting of Andalucast LCV (FSS-1151) cured to 650~F.
The lower end of the combustor 14 is configured to promote thorough burning of the wood fuel 152 fed into the combustor 14.
Generally, the lower end of the combustor 14 includes a refractory cone 80 and a secondary air flow controller 178, shown in Figure 5, for controlling the air 128 flowing from the combustor annulus 72 into the re~ractory cone section 153. The refractory cone 80 serves to accumulate and radiate heat to stabilize initial combustion. In the preferred embodiment, the control of the secondary air flow 128 is accomplished by a plurality of movable vanes 179 which are controlled by a vane actuator 180, shown generally in Figure 4.
For applications that may involve the use of very fine particulate (dust) fuel, it may be necessary to have means for initiating combustions. An embodiment of such a fuel CA 022~8~79 I999-ol-l~
~098/~6869 ~ . PCT~S97/23647 injector 74 ' iS illustrated in Figure 4A. In this embodiment, a liquid fuel line 75 is disposed within the lower end of the combustor 14 to convey fuel to a nozzle 76 positioned proximate the cone 80. This fuel line 75 is protected from extreme the incoming regular ~uel 152 with a barrier 77. The liquid fuel is ignited in any normal manner at the nozzle 76 to raise the temperature of the dust of regular ~uel to initial combustion temperature.
Thereafter, the liquid ~uel ~low can be terminated.
A top view of the vanes 179 is shown in Figure 5. The vanes 179 encircle the exit of the fuel injector 74. Each of the vanes 179 pivots relative to one end such that the vanes 179 can be maneuvered to control air flow therethrough. As shown in Figure 5, the vanes are positioned in a fully open position thereby permittlng a maximum air flow. Controlling the amount of secondary air 128 flowing into the lower end o~ the combustor 14 controls both the secondary air 128 to wood fuel 152 ratio and CA 022~8~79 l999-Ol-l~
W098/46~G~ ~ . PCT~S97/23647 the flame temperature in the re~ractory section 153 of the combustor and promotes swirling of the wood fuel 152 ~or a more thorough combustion o~ the wood ~uel 152. The degree of opening between the vanes 179 is achieved with the actuator 180 which either draws the vanes closer or separates them via the connecting linkage 181.
The combustor ~iner 68 defines a plurality o~ spaced annular slots 70, as shown in Figure 4. The annular slots 70 permit cooling-dilution air 129 ~lowing in the annulus 72 to enter into the combustion zone 122 ~or supporting combustion throughout the combustor 14 and controlling the ~lame and gas temperature. In the preferred embodiment, the combustor liner 68 is manufactured from 0.125 in. thick INCONEL 625, 309 SST or 310 SST.
Cooling-dilution air 129 circulates within the annulus 72 to cool the combustor llner 68.
Pre~erably, the combustor liner 68 is cooled to below the ash slagging temperature such that .
MISSING UPON TIME OF PUBLICATION
CA 022~8~79 lsgg-ol-l~
~0 98/46869 . . - PCT/US97/23647 bypass assembly 104 are provided proximate the exit of the cyclone ash separator 16. In the preferred embodiment, the outer shell 94 oi~ the cyclone 16 ls fabricated from carbon steel or the equivalent. The annulus 98 o:E the cyclone 16 is in communication with the annulus 90 of the communication pipe 84 which ls in communication with the annulus 72 of the combustor 14. Cooling-dilution air 129 is circulated in the annulus 98 between the outer shell 94 and the cyclone liner 96 from the combustor annulus 72. The cooling-dilution air 129 flows around the cyclone liner 96 to cool the cyclone liner 96 and keep the ~iner 96 below slagging temperature. Further, the circulating air serves to cool the outside shell 94 of~ the cyclone 16 to reduce thermal losses.
The ash collector 100 is located at the lower end of the cyclone liner 96 and defines two ash lock hoppers 106, 108 for receiving and holding the ash collected. Each ash lock hopper 106, 108 defines a discharging valve 109 CA 022~8~79 l9ss-ol-l~
W098/4~869 - . PCT~S97/23647 the generator break 125 and emergency shutdown button in the control room. The relief valves 127 are operated by the system pressure.
The air bypass asse~mbly 104 permits and controls the flow of air 128 (air flowing in the annulus 98 of the cyclone 16) combining with the cleaned combustion gas 126 as the gas 126 exits the cyclone 16 through the duct 110.
In the embodiment shown in Figure 4, the air bypass assembly 104 includes a fixed sleeve 182, a control sleeve 185 and an outlet pipe 184. The fixed sleeve 182 is de~ined by the first end of the duct 110 exiting the cyclone 16. The fixed sleeve 182 encircles the outlet pipe 184 in a m~nne~ such that an annular space 186 is defined therebetween. The annular space 186 is unobstructed at the upper end thereof.
The ~ixed sleeve 182 supports the lower end o~
the outlet pipe 184 such that it is retained within the fixed sleeve 182. Further, the fixed sleeve 182 defines a plurality of openings 183 at an upper portion thereof, as shown in Figure 1. The control s~eeve 185 is CA 022~8~79 lggg-ol-l~
W098/46869 ~ . PCT~S97123647 , annularly received by an outer surface of the fixed sleeve 182 proximate the plurality of openings 183 and defines a plurality of openings 187 which correspond to the openings 183 defined by the fixed sleeve 182, as shown in Figure 1. The control sleeve 185 rotates to control the flow of air 128 flowing from the annulus 98 of the cyclone 16 through the upper portion of the annular space 186 dei~ined between the fixed sleeve 182 and the outlet pipe 184. This air 128 combines with the combustion gas 126 exiting the upper end of the outlet pipe 184. In the preferred embodiment, the control sleeve 185 rotates in a limited manner, in one direction to fully block the openings 183 of the fixed sleeve 182 and in the opposing direction to reveal partially or fully the openings 183 of the ~ixed sleeve 182 there~y controlling the flow rate of the tertiary air or cooling-dilution air 129. The lower end of outlet pipe 184 defines a plurality of vents 188. Air ~lowing in the lower portion of the annular space 18 6 serves CA 022~8~79 lgss-ol-l~
W098/46869 . PCT~S97/23647 to cool the outlet pipe 184 and exits through the vents 188 into the entrance of the outlet pipe 184 to combine with the cleaned combustion gas 126.
In an alternate embodiment shown in Figure 6, the air bypass assembly 104 includes a casing 112 sealed around the first end of the duct 110 and a pressure controlled bypass flow valve 114. The first end o~ the duct 110 de~ines a plurality o~ openings 116 open to the casing 112. When the valve 114 is opened, air ~rom the cyclone annulus 98 flows into the casing 112, through the plurality o~ openings 116 and into the duct 110 and combines with the cleaned combustion gas 126. In the pre~erred embodiment, the bypass ~low valve 114 is manufactured ~rom SST 309 or an equivalent ~aterial.
The flame temperature and cyclone exit air temperature are monitored and controlled with excess air by modulating the bypass flow. The bypassed air 128 is directed into the cyclone exit vortex to decrease cyclone pressure loss CA 022~8~79 lsgg-ol-l~
W098/46869 - . PCT~S97/23647 and to increase cyclone e~iciency during operation o~ the system.
In an alternate em~odiment (see Figure 1), a steam injector 118 is in communication with the duct llO to inject steam into the stream o~
cleaned combustion gas 126 and bypassed air for added power. In an alternate embodiment, steam injectors 134 (see Figure 4) are utilized to inject steam into the secondary air 128 at the lower end o~ the combustor 14 and the lower end o~ the cyclone 16.
To begin operation o~ the system 10, the gas generator 18 is rotated at low speed with a hydraulic starter (not shown) to create a gentle dra~t and purge the system 10. Natural gas, oil or LPG is injected into the bottom o~
the combustor 14, through the starter ~uel inlet or gas burner 78, and ignited by a high temperature electrical spark to warm the combustor 14 and cyclone 16 and preheat the re~ractory cone 80. During initial start up and idle the gas burner 78 is utilized and is controlled via the commercial gas burner CA 022~8~79 1999-01-1~
WO 98/46869 - . PCT/US97/Z3647 .
controller 190 which includes a gas pressure control 192 and an air flow control 194.
The gas generator 18 is accelerated by the starter engine, and sawdust fuel 152 injection is started. After the sawdust fuel 152 i8 ignited and the speed of the gas generator turbine 20 is increased by a combination of energy input from the starter engine and the progressively increased combustion rate, the natural gas ~uel/oil is turned off. When the gas generator 18 reaches a self-sustaining energy balance speed, the starter engine is turned of~. Pre~erably, the sawdust fuel feed rate i8 3.5 lb/sec with 2 - 4 lb/sec primary air.
Secondary and tertiary air 128 are supplied from the compressor 21 and function to support combustion and control ~lame and gas temperature. The air 128 enters the combustor via the port 95 at the bottom o~ the combustor 14. In one embodiment, the air enters the port 95 at a rate o~ 121.5 lb/sec, a temperature of 600~F and a pressure of 125 psi with a density CA 022~8~79 I999-Ol-l~
W098/46869 . PCT~S97/23647 o~ 0.318 ft3/sec. The secondary air 128 ~lows through the vanes 179 at the lower end of the combustor 14 and enters the re~ractory section 153. The secondary air 128 flowing through the vanes 179 serves two main ~unctions: to swirl the wood ~uel 152 as it feeds into the re~ractory section 153; and to control the flame temperature in the refractory section 153. The vanes 179 are con~igured such that as lo the air/wood ~uel mixture enters the re~ractory section 153 it establishes a swirling action such that the wood fuel 152 is retained within the re~ractory section 153 for an extended period to encourage more thorough heating of the wood fuel 152, ultimately encouraging combustion o~ all wood ~uel 152. The conditions in the re~ractory section 153 are below stoichiometric conditions such that complete combustion does not take place in the re~ractory section 153.
The majority of the tertiary air 130 enters the combustion zone 154 just above the refractory 80 through a network o~ holes and/or CA 022~8~79 lgss-ol-l~
WO 98/46869 ~ . PCI~/US97/23647 slots 71 dei~ined by the combustor liner 68 to complete combustlon in a super stoichiometric condition. The amount o~ air :Eed into the combustion zone 122 is such that the oxygen content is above stoichiometry. The surface temperatures inside the combustor liner 68 are about 1400~F maximum due to cooling by the cooling-dilution air 129 which is at approximately 640~F. Surf~ace temperatures of the outside of the combustor liner 68 are approximately 910~F while the insulated outer wall of~ the outer shell 66 is about 269~F. The resulting outside ambient air is about 100~F.
The primary air 150 for injection with the wood :Euel 152 comes directly ~rom the compressor 21. When utilizing the sawdust preparation system shown in Figure 2, the air iB fed through a booster f~an. The sawdust i~uel 152 enters ~rom the bottom o~ the pressurized charge vessel assembly 32 and is carried by the primary air 150 to the bottom oi~ the combustor 14 where it is injected. When utilizing the sawdust preparation system depicted in Figure CA 022~8~79 l999-Ol-l~
W0~8/4~86~ - . PCT~S97/23647 , 3, the booster ~an 175, mounted in a pressure vessel 176, is utilized to boost the pressure and temperature of the primary air 150 be~ore it is ultimately delivered to the bottom o~ the combustor 14.
Combustion temperatures inside the re~ractory section 153 at the bottom o~ the combustor 14 reach approximately 2200~F (~or a short period o~ time, e.g., less that 1 sec.) and decrease along the combustor as the cooling-dilution air 129 ~lows into the combustion zones through the combustor annular slots 70. The cooling of the inner wall o~ the combustor liner 68 by the cooling-dilution air 129 ~low prevents slag ~ormation and residue inside the combustor liner wall. The temperature o~ the combustion gas cools to 1600~F maximum as it turns into the communication pipe 84 joining the combustor 14 and the cyclone 16.
Particulates are separated ~rom the combustion gas 125 in the cyclone ash separator 16 and are ultimately collected at the bottom CA 022~8~79 1999-01-1~
W098/46869 - . - PCT~S97/23647 .
in the second ash lock hopper 108. Clean combustion gas 126 exits at the top of the cyclone 16 at a maximum temperature of 1580~F, at 70 lb/sec and at 122 psi. As it exits, the clean combustion gas 126 is mixed with diverted air 128 from the air bypass assembly 104 and then is routed to the turbine 20 via the duct 110, at a pressure o~ approximately 122 psi and a temperature of 1350~F.
The use of the bypass air allows the combustor volume to be reduced. The lower air-gas flow rate through the co~bustor 14 and the cyclone 16 decreases ash carry over and allows the design o~ a more e~icient cyclone 16.
This ~eature reduces the ash grains per cubic foot in the turbine exhaust by 50%.
The gas generator 18 utilized in the system 10 has a split shaft to allow the gas generator turbine 20 and power turbine 19 to rotate at di~ferent revolutions per minute. In the pre~erred embodiment, the gas generator 18 is a modi~ied commercial gas turbine with a special center section and automatic check CA 022~8~79 l999-Ol-l~
W098/~68C~ - . PCT~S97/23647 valves 121 to allow off-board firing without blowback. These automatic check valves 121 reduce the pressure drop between the compressor discharge and the turbine inlet, as well as reducing compressor air back-pressure for easy start of the gas generator.
Upon entering the gas generator turbine 20, the combustion gas 126 expands to produce work. The gas generator turbine 20 powers the air compressor 21 via a drive shaft. The power turbine 19 drives the electrical generator 17 which is linked to any suitable electrical power transmission line. The power in excess of that required to drive the biomass burning system 10 is supplied to the outside user.
There~ore, a load rejection device is not needed due to the internal use of electrical power in the biomass burning system 10 and specifically in the wood drying process and the use of a special brake between the turbine gear box 123 and generator 17. I~ the generator 17 should be disconnected ~rom the power grid or lose its field, the central control system 136 CA 022~8~79 1999-01-1~
W098/46869 . - PCT~S97/23647 would automatically stop the biomass fuel dust, open the pressure relief valves 127 and apply a caliper brake 125 to prevent a generator overspeed.
Steam is injected (as at 118) to boost turbine power a~ter reaching 90% of achievable power by using wood fuel only.
Re~erring to ~igure 7, the control system 22 includes a com~ustion control processor (CCP) 136 which is utilized to monitor and control the biomass burning system 10. The CCP
136 is a distributed process controller that regulates the combustion process and monitors the combustion gas 125 and cleaned combustion gas 126. In the pre~erred embodiment, the distributed process controller is a Bristol Babcock 3335 DPC. The purpose o~ the control system 22 is to monitor functions ~rom the biomass burning system 10, a generator 20-- instrument package (GIP) 140, a turbine instrument package (TIP) 138 and a continuous emissions monitor (CEM) 142, and to use these inputs to provide a safe and e~icient control CA 022~8~79 l999-Ol-l~
W098/468C9 . PCT~S97/23647 o~ the biomass burning system 10 and to instruct the speed tachometer 146 and power controller 148. In the preferred embodiment, the GIP is an Allen Bradley line synchronization module, the TIP is manu~actured by General Electric (model number 7LM1500 GD102), and the CEM is an EPI 410.
Figure 8 illustrates the major CCP input and output signals and controller ~unctions.
Each are labeled according to the various elements o~ the system.
The biomass burning process includes the wood processing and the combustion process.
Selected conditions within the wood processing system 12, the combustor 14, the cyclone 16 and the gas generator 18 are monitored by the CCP
136. Within the wood processing system 12, the temperature o~ the hot exhaust ~or drying and the dryer inlet and outlet air temperatures are monitored. Moisture monitors 63 are located throughout the wood processing system 12 to monitor the moisture o~ the wood ~uel 152 as it is processed ~or use.
CA 022~8~79 Issg-ol-l~
W098/46869 . PCT~S97/23647 In the combustor 14, the temperature of the combustion zone 122 is monitored, and pre~erably the first 154, second 156, fourth 158 and ~ifth zones 160 are individually monitored. Moreover, the temperature at the entrance of the first combustion zone 154 and the temperature at the exit of the first zone 154 are specifically monitored. ~n the preferred embodiment, the temperatures at these various locations are measured with high temperature thermocouples, type S (as at 211 ln Figure 4). The temperature o~ the combustor 122 liner walls is controlled by modulating the cyclone bypass valve 185 to flow the proper amount o~ cooling-dilution air 129 through the combustor cooling annulus 72. The position of the cyclone bypass vlave 185 is controlled by the CCP 136.
The temperature of the pneumatically ~ed ~uel 152, the temperature o~ the primary air 150 a~ter the cooler and a~ter water injection, and the temperature o~ the secondary air 128 CA 022~8~79 lsss-ol-l~
W098/46869 ~ . PCT~S97/23647 before and a~ter steam injection are monitored, pre~erably, wlth type K thermocouples.
Also, the mass flow, the ~uel ~eed rate and pressure in the injection line 173 are monitored. Pre~erably, the mass ~low rate is measured with a Kurz mass flow monitor. The injection line ~uel ~eed rate is measured with a pressure transmitter. The ~eed rate o~ ~uel is a ~unction o~ the revolutions per minute (RPM) of the injector screw. The pressure at the exit of the combustor 1~, the pressure across the pneumatic ~eed booster and the compressor 21 air ~low into the combustor 1 are monitored, pre~erably, with pressure transmitters. Further, the temperature o~ the combustion gas 125 entering the cyclone and the cleaned combustion gas 126 exiting the cyclone are monitored.
In the gas generator 18, the temperature o~ the gas entering and leaving the compressor 21, the temperature o~ the gas entering the gas generator turbine 20, the temperature o~ the gas leaving the power turbine 19, the ~low rate W098/46869 . PCT~S97/23647 o~ air flowing in the gas generator air vent 25 and the pressure at the exit of the compressor 2~ are also monitored with similar transducers Further, the gas generator speed and the power turbine speed are monitored and, in the preferred embodiment, the load of the turbine 19 is also monitored such that the control system 22 can maintain the turbine 19 at a constant speed with a variable load. a more rapid response is provided when both the speed and the load are monitored.
The generator instrument package (GIP) 140 and the turbine instrument package (TIP) 138 function as industrial systems maintaining the turbine 19 and generator 18 ~unctions and monitor certain aspects of the generator 18 and the turbine 19, respectively, such as vibration, lube oil pressure and temperature, power turbine and gas generator RPM, generator 20_ volts, amps etc. The GIP 140 and TIP 138 provide controls ~or shutting down the system when preestablished limits have been passed.
CA 022~8~79 l999-Ol-l~
W098/46869 PCT~S97/23647 The continuous emissions monitor ( CEMS ) 142 controls emissions, regulates combustion and provides environmental reporting.
Speci~ically, the continuous emissions monitor 142 monitors the level o~ carbon monoxide, particulates, and NOX in the turbine exhaust gas. The CEMS controls emlssions by monitoring the exhaust carbon monoxide level and regulating the combustor air via the CCP. The controls are implemented to control the level o~ CO when it exceeds EPA standards.
The in~ormation from the biomass burning system lO, the gas generator 18, the GIP 140, the TIP 138 and the CEMS 142 is utilized to instruct the speed and power controllers 146, 148 such that the biomass burning system 10 operates in a sa~e and e~icient manner.
Speci~ically, the CCP 136 uses a so~tware program to control the steam injector 118 at the exit of the cyclone 16, the steam injectors 134 at the combustor 14 and the cyclone 16 when utilized, the vane actuator 180 ~or controlling the ~low o~ the secondary air 128 into the CA 022~8~79 Issg-ol-l~
W098/46869 , , PCT~S97/23647 combustor 14, the fuel feed injector 74, ~he gas burner controller 190, the air bypass assembly 104 and the thermal relie~ valve, 102, The CCP 136 outputs a current which provides a pressure signal to the vane actuator 180. The air bypass assembly 104 is set according to the system power level. The thermal relief valve 102 is interlocked with the distributed process controller and is opened with a key switch electro-pneumatic system.
The speed of the power turbine 19 is controlled in one o~ two manners depending upon whether the system 10 is linked to an outside system or not. When the biomass burning system 10 is connected to the outside transmission line, the speed is controlled by the 60 cycle balance of the transmission line. However, when the system 10 is connected to an internal load, the speed of the power turbine 19 and the gas generator 18 are under the control o~ the combustion control processor 136. a mechanical speed governor is utilized as a control loop independent of the combustion control processor CA 022~8~79 l999-Ol-l~
~098/46869 . PCT~S97/23647 136 for controlling the speed of the gas generator 18 in the event of a control system 22 failure. The bypass valves 121 are opened and closed during the start cycle according to compressor RPM and compressor discharge pressure schedule, and closed and opened during the shut down process to prevent compressor stalls and surges. These valves 121 are controlled by the CCP 136.
From the foregoing description, it will be recognized by those skilled in the art that a system for burning biomass to produce hot gas offering advantages over the prior art has been provided. Speci~ically, the system for burning biomass provides an improved manner for injecting the wood fuel 152 or biomass into the combustor lg. Further, the control system includes an air bypass assembly 104 for iniecting air into the stream of the combustion gas 126 to control the combustion process. The use of the bypass assembly 104 permits the use of smaller cyclone 16, increases the efficiency of the cyclone filter and controls slagging and CA 02258579 l999-0l-l5 W098/46869 . . PCT~S97~3647 emissions. Also, a thermal relle~ valve 102 is included for rapid cooling of the gas generator turbine 20 and the combustor 14.
While a pre~erred embodiment has been shown and described, it will be understood that it is not intended to limit the disclosure, but rather it is intended to cover all modi~ications and alternate methods falling within the spirit and the scope o~ the invention as de~ined in the appended claims.
Claims (34)
1. A system for burning biomass particles to produce hot gas comprising:
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof, said pressurized combustor including a refractory cone at said lower end thereof which defines an initial combustion zone, said refractory cone accumulating and radiating heat to stabilize initial combustion of the biomass particles as they enter said initial combustion zone;
a feeding device for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication pipe, said communication pipe defining a second annulus in communication with said first annulus, said cyclone ash separator defining a cyclone shell, a cyclone liner, a third annulus therebetween, and a duct, said third annulus being in communication with said second annulus, said duct for ducting said combustion gas into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor for circulating compressed air in said first, second and third annuluses via said port, said air compressor being driven by said gas generator turbine, said compressed air entering said combustion zone through said at least one annular opening, said compressed air facilitating said combustion mechanism; and, a control system for controlling said rotational speed of said gas generator turbine and a biomass particle feed rate into said pressurized combustor.
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof, said pressurized combustor including a refractory cone at said lower end thereof which defines an initial combustion zone, said refractory cone accumulating and radiating heat to stabilize initial combustion of the biomass particles as they enter said initial combustion zone;
a feeding device for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication pipe, said communication pipe defining a second annulus in communication with said first annulus, said cyclone ash separator defining a cyclone shell, a cyclone liner, a third annulus therebetween, and a duct, said third annulus being in communication with said second annulus, said duct for ducting said combustion gas into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor for circulating compressed air in said first, second and third annuluses via said port, said air compressor being driven by said gas generator turbine, said compressed air entering said combustion zone through said at least one annular opening, said compressed air facilitating said combustion mechanism; and, a control system for controlling said rotational speed of said gas generator turbine and a biomass particle feed rate into said pressurized combustor.
2. The system for burning biomass of Claim 1 wherein said pressurized combustor defines a means for controlling an air flow from said first annulus through said bottom of said pressurized combustor to promote swirling of the biomass particles.
3. The system for burning biomass of Claim 2 wherein said means for controlling an air flow includes a plurality of vanes and a vane actuator, said plurality of vanes encircling an exit of said feeding device within said first annulus at a lower end of said pressurized combustor, each of said plurality of vanes pivoting with respect to one end, said vane actuator for controlling said pivoting of said plurality of vanes thereby controlling a spacing between each of said plurality of vanes.
4. The system for burning biomass of Claim 1 wherein said pressurized combustor defines a means for controlling an air flow from said first annulus through said bottom of said pressurized combustor to promote swirling of the biomass particles.
5. The system for burning biomass of Claim 4 wherein said means for controlling an air flow includes a plurality of vanes and a vane actuator, said plurality of vanes encircling an exit of said feeding device within said first annulus at a lower end of said pressurized combustor, each of said plurality of vanes pivoting with respect to one end, said vane actuator for controlling said pivoting of said plurality of vanes thereby controlling a spacing between each of said plurality of vanes.
6. The system for burning biomass of Claim 1 wherein said control system includes an air bypass assembly for permitting and controlling a flow of bypass air into said duct from said third annulus of said cyclone ash separator, said bypass air combining with said combustion gas in said duct.
7. The system for burning biomass of Claim 6 wherein said air bypass assembly defines a fixed sleeve, an outlet pipe and a control sleeve, said fixed sleeve being defined by a first end of said duct, said outlet pipe being received within and supported by said fixed sleeve in a manner such that a fourth annulus is defined therebetween, an upper end of said fourth annulus being unobstructed and in communication with said duct, said control sleeve being annularly received by an outer surface of said fixed sleeve and being rotatable about said fixed sleeve, said upper end of said fixed sleeve defining a plurality of first openings, said control sleeve defining a plurality of second openings each of which corresponding to each of said plurality of first openings, said control sleeve being in communication with said third annulus of said cyclone ash separator, said control sleeve rotating around said fixed sleeve to control the amount of the plurality of first openings revealed thereby controlling the amount of said compressed air within said third annulus flowing through said first and second plurality of openings and into said fourth annulus.
8. The system for burning biomass of Claim 6 wherein said air bypass assembly defines a casing and a bypass flow valve, said duct defining a plurality of openings at a first end thereof, said casing enclosing an outer surface of said first end of said duct, said bypass flow valve being in communication with said third annulus of said cyclone ash separator, said bypass flow valve permitting a flow of a portion of said compressed air in said third annulus to flow into said casing and through said plurality of openings of said duct to mix with said combustion gas entering said duct.
9. The system for burning biomass of Claim 1 wherein said control system includes a thermal relief valve in communication with said duct proximate an exit of said cyclone ash separator for the release of said combustion gas.
10. The system for burning biomass of Claim 1 wherein said cyclone ash separator further includes at least one ash lock hopper for receiving and retaining the ash removed from said combustion gas.
11. The system for burning biomass of Claim 1 further including a wood processing system for processing and preparing the biomass for injection into said system.
12. The system for burning biomass of Claim 11 wherein said wood processing system includes air swept pulverizers which pulverize, dry and classify the biomass.
13. A system for burning biomass particles to produce hot gas comprising:
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof;
a feeding device for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication pipe, said communication pipe defining a second annulus in communication with said first annulus, said cyclone ash separator defining a cyclone shell, a cyclone liner, a third annulus therebetween, and a duct, said third annulus being in communication with said second annulus, said duct for ducting said combustion gas into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor for circulating compressed air in said first, second and third annuluses via said port, said air compressor being driven by said gas generator turbine, said compressed air entering said combustion zone through said at least one annular opening, said compressed air facilitating said combustion mechanism; and, a control system for controlling said rotational speed of said gas generator turbine, said control system including an air bypass assembly for permitting and controlling a flow of bypass air into said duct from said third annulus of said cyclone ash separator, said bypass air combining with said combustion gas in said duct.
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof;
a feeding device for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication pipe, said communication pipe defining a second annulus in communication with said first annulus, said cyclone ash separator defining a cyclone shell, a cyclone liner, a third annulus therebetween, and a duct, said third annulus being in communication with said second annulus, said duct for ducting said combustion gas into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor for circulating compressed air in said first, second and third annuluses via said port, said air compressor being driven by said gas generator turbine, said compressed air entering said combustion zone through said at least one annular opening, said compressed air facilitating said combustion mechanism; and, a control system for controlling said rotational speed of said gas generator turbine, said control system including an air bypass assembly for permitting and controlling a flow of bypass air into said duct from said third annulus of said cyclone ash separator, said bypass air combining with said combustion gas in said duct.
14. The system for burning biomass of Claim 13 wherein said pressurized combustor includes a refractory cone at lower end thereof which defines an initial combustion zone, said refractory cone accumulating and radiating heat to stabilize initial combustion of the biomass particles as they enter said initial combustion zone.
15. The system for burning biomass of Claim 13 wherein said pressurized combustor defines a means for controlling an air flow from said first annulus through said bottom of said pressurized combustor to promote swirling of the biomass particles.
16. The system for burning biomass of Claim 15 wherein said means for controlling an air flow includes a plurality of vanes and a vane actuator, said plurality of vanes encircling an exit of said feeding device within said first annulus at a lower end of said pressurized combustor, each of said plurality of vanes pivoting with respect to one end, said vane actuator for controlling said pivoting of said plurality of vanes thereby controlling a spacing between each of said plurality of vanes.
17. The system for burning biomass of Claim 14 wherein said pressurized combustor defines a means for controlling an air flow from said first annulus through said bottom of said pressurized combustor to promote swirling of the biomass particles.
18. The system for burning biomass of Claim 17 wherein said means for controlling an air flow includes a plurality of vanes and a vane actuator, said plurality of vanes encircling an exit of said feeding device within said first annulus at a lower end of said pressurized combustor, each of said plurality of vanes pivoting with respect to one end, said vane actuator for controlling said pivoting of said plurality of vanes thereby controlling a spacing between each of said plurality of vanes.
19. The system for burning biomass of Claim 13 wherein said air bypass assembly defines a fixed sleeve, an outlet pipe and a control sleeve, said fixed sleeve being defined by a first end of said duct, said outlet pipe being received within and supported by said fixed sleeve in a manner such that a fourth annulus is defined therebetween, an upper end of said fourth annulus being unobstructed and in communication with said duct, said control sleeve being annularly received by an outer surface of said fixed sleeve and being rotatable about said fixed sleeve, said upper end of said fixed sleeve defining a plurality of first openings, said control sleeve defining a plurality of second openings each of which corresponding to each of said plurality of first openings, said control sleeve being in communication with said third annulus of said cyclone ash separator, said control sleeve rotating around said fixed sleeve to control the amount of the plurality of first openings revealed thereby controlling the amount of said compressed air within said third annulus flowing through said first and second plurality of openings and into said fourth annulus.
20. The system for burning biomass of Claim 13 wherein said air bypass assembly defines a casing and a bypass flow valve, said duct defining a plurality of openings at a first end thereof, said casing enclosing an outer surface of said first end of said duct, said bypass flow valve being in communication with said third annulus of said cyclone ash separator, said bypass flow valve permitting a flow of a portion of said compressed air in said third annulus to flow into said casing and through said plurality of openings of said duct to mix with said combustion gas entering said duct.
21. The system for burning biomass of Claim 13 wherein said control system includes a thermal relief valve in communication with said duct proximate an exit of said cyclone ash separator for the release of said combustion gas.
22. The system for burning biomass of Claim 13 wherein said cyclone ash separator further includes at least one ash lock hopper for receiving and retaining the ash removed from said combustion gas.
23. The system for burning biomass of Claim 13 further including a wood processing system for processing and preparing the biomass for injection into said system.
24. The system for burning biomass of Claim 23 wherein said wood processing system includes air swept pulverizers which pulverize, dry and classify the biomass.
25. A system for burning biomass particles to produce hot gas comprising:
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof;
a feeding device, including a biomass particle preparation system, for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication, said cyclone ash separator including a gas output duct for ducting said combustion gas with ash removed into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor driven by said gas generator turbine, air compressed by said air compressor entering said pressurized combustor through a check valve facilitating said combustion mechanism;
an automatic bypass check valve system communicating between said air compressor and said gas generator turbine providing for controlled communication between said air compressor and said gas generator turbine for reducing back pressure during initiation of operation of said gas generator turbine; and a control system for controlling said rotational speed of said gas generator turbine, said control system including an air bypass assembly for permitting and controlling a flow of bypass air into said gas output duct of said cyclone separator, said bypass air combining with said combustion gas in said gas output duct.
a gas generator turbine defining a plurality of blades;
a pressurized combustor including a combustion mechanism for the combustion of the biomass particles within a combustion zone thereby producing combustion gas, said pressurized combustor defining an outer shell, a combustor liner and a first annulus between said outer shell and said combustor liner, said combustor liner including at least one annular opening, said outer shell defining a port at a lower end thereof;
a feeding device, including a biomass particle preparation system, for feeding the biomass particles into the bottom of said pressurized combustor;
a cyclone ash separator for removing ash from said combustion gas, said cyclone ash separator communicating with said pressurized combustor via a communication, said cyclone ash separator including a gas output duct for ducting said combustion gas with ash removed into said gas generator turbine to rotate said gas generator turbine at a rotational speed;
an air compressor driven by said gas generator turbine, air compressed by said air compressor entering said pressurized combustor through a check valve facilitating said combustion mechanism;
an automatic bypass check valve system communicating between said air compressor and said gas generator turbine providing for controlled communication between said air compressor and said gas generator turbine for reducing back pressure during initiation of operation of said gas generator turbine; and a control system for controlling said rotational speed of said gas generator turbine, said control system including an air bypass assembly for permitting and controlling a flow of bypass air into said gas output duct of said cyclone separator, said bypass air combining with said combustion gas in said gas output duct.
26. The system of Claim 25 wherein said biomass particle preparation system comprises:
a source of particulate biomass;
a transport means for delivering said particulate biomass into an aspirator bin;
a pulverizer means for receiving said particulate biomass from said aspirator bin for comminuting said particulate biomass;
a cyclone connected to said pulverizer;
means for drawing comminuted biomass material from said pulverizer and swirling said comminuted biomass material in said cyclone for drying said comminuted biomass material;
a transfer means for conveying dried comminuted biomass material to a live bin cyclone for further drying;
a live bin for receiving and storing said further dried comminuted biomass material from said live bin cyclone, said live bin provided with an output;
metering means at said output of said live bin for metering out said further dried comminuted biomass material;
a lock vessel for accumulating an output of said metering means;
a charging vessel to receive further dried comminuted biomass material from said lock vessel; and a further metering means at an output of said charging vessel for delivering a selected quantity of said further dried comminuted biomass material to said pressurized combustor.
a source of particulate biomass;
a transport means for delivering said particulate biomass into an aspirator bin;
a pulverizer means for receiving said particulate biomass from said aspirator bin for comminuting said particulate biomass;
a cyclone connected to said pulverizer;
means for drawing comminuted biomass material from said pulverizer and swirling said comminuted biomass material in said cyclone for drying said comminuted biomass material;
a transfer means for conveying dried comminuted biomass material to a live bin cyclone for further drying;
a live bin for receiving and storing said further dried comminuted biomass material from said live bin cyclone, said live bin provided with an output;
metering means at said output of said live bin for metering out said further dried comminuted biomass material;
a lock vessel for accumulating an output of said metering means;
a charging vessel to receive further dried comminuted biomass material from said lock vessel; and a further metering means at an output of said charging vessel for delivering a selected quantity of said further dried comminuted biomass material to said pressurized combustor.
27. A processing system for processing and preparing biomass fuel for injection into a combustion system using the biomass fuel, said processing system comprising:
a source of particulate biomass;
a transport means for delivering said particulate biomass into an aspirator bin;
a pulverizer means for receiving said particulate biomass from said aspirator bin for comminuting said particulate biomass;
a cyclone connected to said pulverizer;
means for drawing comminuted particulate biomass from said pulverizer and swirling said comminuted particulate biomass in said cyclone for drying said comminuted particulate biomass;
a transfer means for conveying dried comminuted particulate biomass to a live bin cyclone for further drying;
a live bin for receiving and storing said further dried comminuted particulate biomass from said live bin cyclone, said live bin provided with an output;
metering means at said output of said live bin for metering out said further dried comminuted particulate biomass;
a lock vessel for accumulating an output of said metering means;
a charging vessel to receive further dried comminuted particulate biomass from said lock vessel; and a further metering means at an output of said charging vessel for delivering a selected quantity of said further dried comminuted particulate biomass to a combustor of the combustion system.
a source of particulate biomass;
a transport means for delivering said particulate biomass into an aspirator bin;
a pulverizer means for receiving said particulate biomass from said aspirator bin for comminuting said particulate biomass;
a cyclone connected to said pulverizer;
means for drawing comminuted particulate biomass from said pulverizer and swirling said comminuted particulate biomass in said cyclone for drying said comminuted particulate biomass;
a transfer means for conveying dried comminuted particulate biomass to a live bin cyclone for further drying;
a live bin for receiving and storing said further dried comminuted particulate biomass from said live bin cyclone, said live bin provided with an output;
metering means at said output of said live bin for metering out said further dried comminuted particulate biomass;
a lock vessel for accumulating an output of said metering means;
a charging vessel to receive further dried comminuted particulate biomass from said lock vessel; and a further metering means at an output of said charging vessel for delivering a selected quantity of said further dried comminuted particulate biomass to a combustor of the combustion system.
28. The processing system of Claim 27 further comprising:
a second aspirator bin for receiving particulate biomass from said transport means;
a second pulverizer means for receiving said particulate from said second aspirator bin for comminuting said particulate biomass;
a second cyclone connected to said second pulverizer;
second means for drawing comminuted particulate biomass from said second pulverizer means and swirling said comminuted particulate biomass into said second cyclone for drying said comminuted particulate biomass;
a second transfer means for conveying dried comminuted particulate biomass into a second cyclone for further drying for deposit in said transfer means.
a second aspirator bin for receiving particulate biomass from said transport means;
a second pulverizer means for receiving said particulate from said second aspirator bin for comminuting said particulate biomass;
a second cyclone connected to said second pulverizer;
second means for drawing comminuted particulate biomass from said second pulverizer means and swirling said comminuted particulate biomass into said second cyclone for drying said comminuted particulate biomass;
a second transfer means for conveying dried comminuted particulate biomass into a second cyclone for further drying for deposit in said transfer means.
29. The system of Claim 27 further comprising a second lock vessel in parallel with said lock vessel for accumulating said output of said metering means and for conveying dried comminuted particulate biomass to said charging vessel.
30. The system of Claim 27 wherein said transfer means from said cyclone and said second cyclone to said live bin is a pneumatically operated transfer conduit.
31. The system of Claim 27 wherein said metering means at an output of said live bin is a reversing cross auger and a plurality of feed augers.
32. The system of Claim 28 further comprising vibrator means attached to said side walls of said lock vessel, of said second lock vessel and of said charge vessel.
33. A processing system for processing and preparing biomass fuel for injection into a combustion system using the biomass fuel, said processing system comprising:
a source of particulate biomass;
a transport means for delivering said particulate biomass into a first aspirator bin and a second aspirator bin;
a first pulverizer means for receiving said particulate biomass from said first aspirator bin for comminuting said particulate biomass;
a second pulverizer means for receiving said particulate biomass from said second aspirator bin for comminuting said particulate biomass;
a first cyclone connected to an output of said first pulverizer means;
a second cyclone connected to an output of said second pulverizer means;
a first withdrawal means for drawing comminuted particulate biomass from said first pulverizer means and swirling said comminuted particulate biomass in said first cyclone for drying said comminuted particulate biomass;
a second withdrawal means for drawing comminuted particulate biomass from said second pulverizer means and swirling said comminuted particulate biomass in said second cyclone for drying said comminuted particulate biomass;
a transfer means for conveying dried comminuted particulate biomass from said first and second cyclones to a live bin for accumulating said dried comminuted particulate biomass, said live bin provided with an output;
metering means at said output of said live bin for metering out said dried comminuted particulate biomass;
a first lock vessel for receiving material from said metering means;
a second lock vessel for receiving material from said metering means;
a charging vessel from receiving material from said first and second lock vessels; and a further metering means at an output of said charging vessel for delivering a selected quantity of said dried comminuted particulate material to a combustor of the combustion system.
a source of particulate biomass;
a transport means for delivering said particulate biomass into a first aspirator bin and a second aspirator bin;
a first pulverizer means for receiving said particulate biomass from said first aspirator bin for comminuting said particulate biomass;
a second pulverizer means for receiving said particulate biomass from said second aspirator bin for comminuting said particulate biomass;
a first cyclone connected to an output of said first pulverizer means;
a second cyclone connected to an output of said second pulverizer means;
a first withdrawal means for drawing comminuted particulate biomass from said first pulverizer means and swirling said comminuted particulate biomass in said first cyclone for drying said comminuted particulate biomass;
a second withdrawal means for drawing comminuted particulate biomass from said second pulverizer means and swirling said comminuted particulate biomass in said second cyclone for drying said comminuted particulate biomass;
a transfer means for conveying dried comminuted particulate biomass from said first and second cyclones to a live bin for accumulating said dried comminuted particulate biomass, said live bin provided with an output;
metering means at said output of said live bin for metering out said dried comminuted particulate biomass;
a first lock vessel for receiving material from said metering means;
a second lock vessel for receiving material from said metering means;
a charging vessel from receiving material from said first and second lock vessels; and a further metering means at an output of said charging vessel for delivering a selected quantity of said dried comminuted particulate material to a combustor of the combustion system.
34. The system of Claim 33 wherein said metering means and said further metering means are auger units to transfer controlled quantities of said dried comminuted particulate biomass.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US84274897A | 1997-04-16 | 1997-04-16 | |
US08/842,748 | 1997-04-16 |
Publications (1)
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CA2258579A1 true CA2258579A1 (en) | 1998-10-22 |
Family
ID=25288164
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002258579A Abandoned CA2258579A1 (en) | 1997-04-16 | 1997-12-18 | System for burning biomass to produce hot gas |
Country Status (5)
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AU (1) | AU5712598A (en) |
BR (1) | BR9710691A (en) |
CA (1) | CA2258579A1 (en) |
NO (1) | NO985899L (en) |
WO (1) | WO1998046869A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2348695A (en) | 1999-04-06 | 2000-10-11 | James Engineering | Gas turbines |
SE531817C2 (en) * | 2006-10-18 | 2009-08-18 | Martin Larsson | Vehicle engine and vehicle comprising such an engine |
US9790834B2 (en) | 2014-03-20 | 2017-10-17 | General Electric Company | Method of monitoring for combustion anomalies in a gas turbomachine and a gas turbomachine including a combustion anomaly detection system |
US9791351B2 (en) | 2015-02-06 | 2017-10-17 | General Electric Company | Gas turbine combustion profile monitoring |
CN109059002A (en) * | 2018-08-01 | 2018-12-21 | 合肥右传媒科技有限公司 | A kind of refuse disposal installation |
CN111156106B (en) * | 2020-01-13 | 2021-07-20 | 绍兴钱康机械科技有限公司 | Heat accumulating type waste gas incinerator |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2171535A (en) * | 1935-03-08 | 1939-09-05 | Charles W Nichols Sr | Incineration of high moisture refuse |
US4409786A (en) * | 1977-06-30 | 1983-10-18 | Biomass Energy Systems, Incorporated | Wood burning system and method |
US5341637A (en) * | 1992-12-22 | 1994-08-30 | Hamrick Joseph T | System for burning biomass to fuel a gas turbine |
-
1997
- 1997-12-18 AU AU57125/98A patent/AU5712598A/en not_active Abandoned
- 1997-12-18 BR BR9710691-7A patent/BR9710691A/en not_active Application Discontinuation
- 1997-12-18 CA CA002258579A patent/CA2258579A1/en not_active Abandoned
- 1997-12-18 WO PCT/US1997/023647 patent/WO1998046869A1/en active Application Filing
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1998
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NO985899L (en) | 1999-02-02 |
NO985899D0 (en) | 1998-12-16 |
BR9710691A (en) | 2000-01-11 |
WO1998046869A1 (en) | 1998-10-22 |
AU5712598A (en) | 1998-11-11 |
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