EP4018124A1 - Chaudière-séchoir hybride et procédé associé - Google Patents

Chaudière-séchoir hybride et procédé associé

Info

Publication number
EP4018124A1
EP4018124A1 EP20764232.3A EP20764232A EP4018124A1 EP 4018124 A1 EP4018124 A1 EP 4018124A1 EP 20764232 A EP20764232 A EP 20764232A EP 4018124 A1 EP4018124 A1 EP 4018124A1
Authority
EP
European Patent Office
Prior art keywords
bed
fuel
furnace
flue gas
contaminants
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20764232.3A
Other languages
German (de)
English (en)
Inventor
Frederic Vitse
Steven Unker
Carl Edberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Technology GmbH
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US16/548,167 external-priority patent/US11142717B2/en
Application filed by General Electric Co filed Critical General Electric Co
Publication of EP4018124A1 publication Critical patent/EP4018124A1/fr
Pending legal-status Critical Current

Links

Classifications

    • 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 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/002—Fluidised bed combustion apparatus for pulverulent solid fuel
    • 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 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/003—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for pulverulent fuel
    • 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 
    • F23C2202/00—Fluegas recirculation
    • F23C2202/50—Control of recirculation rate
    • 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 
    • F23C2206/00—Fluidised bed combustion

Definitions

  • Embodiments of the invention relate generally to solid fuel boilers and more specifically to a hybrid boiler-fuel dryer and method.
  • the steam After the steam has passed through the turbine, it is provided to a condenser and cooled by passing around pipes carrying cooling water, which absorb the heat from the steam. As the steam cools, it condenses into water which is then pumped back to the boiler to repeat the process of heating it into steam.
  • High moisture content in solid fuels can also lead to problems in areas such as fuel handling, fuel grinding, fan capacity, and flue gas flow rate.
  • efficient suspension or tangential firing is also affected by the relative moisture content and particle size distribution of the fuel. If the moisture content of the fuel is sufficiently high, the combustion of the fuel in the combustion chamber may be slowed or delayed, resulting in unburnt combustible material being carried out with the flue gas. Further, if a particle size of the pulverized solid fuel is sufficiently large, the larger fuel particle size will make it difficult to maintain the fuel particles in suspension in the combustion chamber, thereby reducing the residence time the particle spends at a high temperature to complete the combustion of the entire particle.
  • the high moisture content fuel must be sufficiently dried and sized.
  • both the particle size and moisture content of the fuel must be addressed (i.e., minimized) in a fuel pretreatment system.
  • a drier apparatus is employed prior to combustion to pre-treat (that is, by heating) the high moisture content fuels to reduce the moisture content and enhance the BTU production of the fuel.
  • Some conventional boilers attempt to circumvent the challenge of combusting fuel having relatively large and moist particles, by employing a semi-suspension system.
  • relatively large fuel particles e.g., greater that 25 mm diameter
  • fines are screened during pretreatment and partially dried in a separate pulverizer drier prior to being fired in suspension.
  • a particle moisture content of 55% and a maximum particle size of less than 40 mm is required (90% at ⁇ 25mm).
  • MCR maximum continuous rating
  • a residence time of a few seconds may be sufficient for drying to 20% moisture, for larger particle sizes residence times of minutes may be necessary for effective drying.
  • conventional driers to be economically viable for fuel drying prior to pulverizing, it preferably would have a residence time of few seconds or less so this can be done while the particles are pneumatically conveyed to the furnace.
  • the corresponding heat and mass transfer rates in such a drier can typically only be achieved using a fluidizing or entrained reactor with a fuel particle size of 1 mm or less. Achieving such particle sizes with a conventional coal mill has been cost prohibitive in terms of milling power. Additionally, the energy expenditure required to grind the fuel increases significantly as the moisture content of the fuel rises from 20% to 40% and above.
  • coal and/or biomass fuels often contain contaminants, i.e., gaseous elements and/or chemicals that cause corrosion, fouling, slagging and/or are otherwise undesirable within a boiler and/or surrounding environment, which are emitted upon firing of the fuels in a furnace.
  • a method for reducing the emission of contaminants by a furnace includes forming a bed from a stream of fuel within the furnace; fluidizing the bed with flue gas from the furnace; and heating the fuel within the bed so as to generate char, ash and contaminants.
  • the method further includes capturing the contaminants via the ash.
  • a furnace in another embodiment, includes a grate operative to form a bed from a stream of fuel, and a conduit operative to fluidize the bed with a flue gas generated by the furnace.
  • the bed facilitates: generation of char, ash and contaminants from the fuel; and capture of the contaminants by the ash.
  • a non-transitory computer readable medium including instructions.
  • the instructions adapt at least one processor to: adjust at least one property of a bed formed by a stream of fuel within a furnace to facilitate: generation of char, ash and contaminants from the fuel; and capture of the contaminants by the ash.
  • FIG. 1 is a schematic diagram of an embodiment
  • FIG. 2 is a schematic diagram of an alternative embodiment
  • FIG. 3 is a flow diagram according an embodiment of a method
  • FIG. 4 is a schematic diagram according to an embodiment
  • FIG. 5 is a schematic diagram of yet another alternative embodiment
  • FIG. 6 is a schematic diagram of yet another embodiment.
  • FIG. 7 is another schematic diagram of the embodiment of FIG. 6.
  • the terms “substantially,” “generally,” and “about” indicate conditions within reasonably achievable manufacturing and assembly tolerances, relative to ideal desired conditions suitable for achieving the functional purpose of a component or assembly.
  • connection may include a direct conductive connection, i.e., without an intervening capacitive, inductive or active element, an inductive connection, a capacitive connection, and/or any other suitable electrical connection. Intervening components may be present.
  • the term “fluidly connected” means that the referenced elements are connected such that a fluid (to include a liquid, gas, and/or plasma) may flow from one to the other. Accordingly, the terms “upstream” and “downstream,” as used herein, describe the position of the referenced elements with respect to a flow path of a fluid and/or gas flowing between and/or near the referenced elements. Further, the term “stream,” as used herein with respect to particles, means a continuous or near continuous flow of particles. As also used herein, the term “heating contact” means that the referenced objects are in proximity of one another such that heat/thermal energy can transfer between them.
  • FIG. 1 a schematic diagram of an embodiment of a solid-fuel type power plant 90 for the generation of electricity is shown.
  • the power plant 90 is operative to increase the temperature and pressure of a gas to drive one or more turbines.
  • the rotating turbines are coupled to alternators by a shaft or rotor to generate AC electricity therewith.
  • the power plant 90 includes a boiler 100 which includes a furnace 250 configured to burn a solid fuel 120 therein.
  • the solid fuel 120 in particulate form is fed from a storage area 140 such as a coal bunker to the boiler 100 in which it is combusted to produce heat.
  • the furnace 250 is operative to ignite and combust the solid fuel 120 in a known manner.
  • the boiler 100 may employ a conventional firing system 102 such as a suspension firing system to combust the fuel 120.
  • a conventional firing system 102 such as a suspension firing system
  • Other embodiments may include other types of conventional furnace firing systems 102 without departing from the scope of the claims herein.
  • the furnace 250 may include a conventional back-pass portion 252 (FIG. 2).
  • a relatively hot flue gas 270 is produced by the combustion of the fuel 120 (FIG. 1) in the furnace 250 and provided to a flue 257 and vented therefrom, for example via an exhaust stack 259.
  • flue 257 may be defined by one or more ducts arranged to receive the hot flue gas 270 produced in furnace 250.
  • at least a first portion 271 (FIG. 4) and a second portion 272 (FIG. 4) of the hot flue gas 270 may be extracted from the flue 257 and recycled to enable the operation of the various embodiments described herein.
  • one or more pollution control devices may be arranged to receive the hot flue gas 270 from the flue 257.
  • a scrubber 268, such as a conventional wet scrubber may be arranged in fluid communication with the flue 257 to receive the flue gas 270 therefrom to extract pollutants such as sulfur compounds, oxides of sulfur (e.g., sulfur dioxide) and ash particles from the flue gas 270 prior to extracting and recycling the first and second portions 271, 272 of the flue gas 270.
  • pollutants such as sulfur compounds, oxides of sulfur (e.g., sulfur dioxide) and ash particles from the flue gas 270 prior to extracting and recycling the first and second portions 271, 272 of the flue gas 270.
  • the boiler 100 further includes a hybrid boiler-dryer 900.
  • the hybrid boiler-dryer 900 include a first fuel dryer 901, and a second fuel dryer 902.
  • the first fuel dryer 901 may include in-suspension fuel dryer
  • the second fuel dryer 902 may include an on-grate fuel dryer.
  • fuel dryer means any apparatus that is useful for the reduction of the moisture content of a particulate material through the application of direct or indirect heat, including but not limited to a fluidized bed dryer, vibratory fluidized bed dryer, fixed bed dryer, traveling bed dryer, cascaded whirling bed dryer, or elongated slot dryer.
  • steam turbine 340 may include a plurality of turbines, such as a high-pressure steam turbine 360, intermediate-pressure steam turbine 380, and low-pressure steam turbines 480 operatively connected in series.
  • the steam 330 performs work by pushing against the fanlike blades (not shown) connected to a series of wheels (not shown) contained within each turbine 340, 360, 380 which are mounted on a shaft (not shown). As the steam 330 pushes against the blades (not shown), it causes both the wheels and turbine shaft to spin.
  • the solid fuel 120 (such as relatively high-moisture content raw coal), may be collected in the storage area 140 (FIG. 1) such as a coal bunker until needed.
  • the high-moisture content fuel 120 may include a first portion 121 of fuel (as indicated in FIG. 4 by arrow 121) defining relatively small particle sizes, or “fines” (e.g., less than 25 mm diameter), and a second portion of fuel 122 (as indicated in FIG.
  • the first portion of fuel 121 further defines predetermined particle sizes that are appropriate for burning by the firing system 102 without need of milling or other steps to reduce the particle sizes within the first portion of fuel 121 ; and the second portion of fuel 122 defines predetermined particle sizes that need milling or other steps to reduce the particle sizes within the second portion of fuel 122 to enable burning by firing system 102.
  • the raw fuel 120 is provided or conveyed using a conventional conveyor device 114 to a filter or sieve 116 for screening.
  • the sieve 116 is operative to separate the first portion of fuel 121 from the second portion of fuel 122 based on the relative particle sizes of the first and second portions of fuel 121, 122.
  • the sieve 116 may include a roller screen.
  • the sieve 116 may include one or more of a centrifuge, trommel screener, vibratory screener, screw feeder, and rotating drum feeder.
  • any desired sieve 116 device may be used to separate the first portion of fuel 121 from the second portion of fuel 122 that enables the furnace to operate as described herein without departing from the scope of the claimed subject matter.
  • the first portion of fuel 121 may then be provided to the firing system 102 of furnace 250 for burning via the first fuel-dryer 901.
  • the first fuel- dryer 901 include a first channel or duct 371 through which the first portion of fuel 121 is conveyed by a flow of the first portion of the flue gas 271.
  • the first duct 371 is configured to receive the first portion of coal 121 directly from the sieve 116.
  • the first duct 371 is configured to receive the first portion of coal 121 from a first conveyor 222 such as a pressurized duct coupled in fluid communication therebetween the first duct 371 and the sieve 116.
  • the first conveyer 222 may be a mechanical type first conveyor 222 such as a belt conveyor or chute, or any other conventional conveyor that enables the first portion of coal 121 to be received by the first duct 371 from sieve 116.
  • the first duct 371 is arranged in fluid communication with the flue 257 to receive the first portion of the flue gas 271 therefrom.
  • the first portion of the flue gas 271 flows through the first duct 371 to thereby convey the first portion of fuel 121 therethrough to the furnace 250 for burning by firing system 102.
  • the first portion of flue gas 271 may be provided using a first air fan 111, such as a primary air fan, in fluid communication with first duct 371.
  • the first air fan 111 may include a flue gas recirculation fan.
  • the heat from the recycled first portion of flue gas 271 is advantageously used to further dry the first portion of fuel 121 while in suspension within the first duct 371 prior to combustion in the furnace 250, for example by suspension or tangential firing.
  • the second portion of fuel 122 may be further dried and sized before being provided to the firing system 102 for burning in furnace 250.
  • the second portion of fuel 122 is dried by the second fuel dryer 902.
  • the second fuel dryer 902 may include a grate 400 having openings (not shown) defined therethrough and configured to receive the second portion of fuel 122 thereon and disposed within a lower portion 251 of furnace 250 proximal the firing system 102.
  • the second portion of fuel 122 is conveyed to the furnace 250 from sieve 116 and disposed on the grate 400 by a second conveyor 255, such as a conventional mechanical belt-type conveyor.
  • the second conveyor 255 may include a pressurized duct.
  • the second portion of fuel 122 is thereby exposed to heat and a reducing environment due to the combustion occurring in the furnace 250, as well as being fluidized by the oxygen deficient exhaust gas stream 272, whereby the second portion of fuel 122 is at least partially devolatilized and dried in a known manner.
  • the second portion of fuel 122 disposed on the grate 400 defines a bed region 440, also referred to herein simply as a “bed”, wherein fluidization occurs.
  • the bed region 440 may include one of a fixed bed, fluidized bed, a bubbling fluidized bed, or sluggish fluidized bed.
  • ash particles produced by the combustion in furnace 250 and present in the bed region 440 may be separated from the second portion of fuel 122.
  • the fixed bed region 440 is coupled in fluid communication with an ash separator 444, whereby the relatively heavier ash particles in the second portion of fuel 122 migrate to the bottom of the bed region 440, and are captured for disposal in an ash receptacle 475 coupled via outlet 410 in fluid communication with the bottom of the bed region 440.
  • a residence time of the bed region 440 (i.e., the period of time that the second portion of fuel 122 remains in the bed region 440 in furnace 250), may be based on a predetermined time period.
  • the residence time of the second portion of fuel 122 in bed 440 may be determined based on the desired properties of the second portion of fuel 122, such as a predetermined moisture content.
  • a second channel or duct 372 is arranged in fluid communication with the flue 257 and configured to receive a second portion 272 of the flue gas exiting the furnace 250 therethrough.
  • the second portion of flue gas 272 is directed via the second duct 372 to the second fuel dryer 902 to fluidize the second portion of fuel 122 disposed in the bed 440.
  • Some embodiments may include any number of second ducts 372 to convey the second portion of flue gas 272 to the second fuel dryer 902.
  • the second portion of flue gas 272 may be provided to a plenum 450 disposed beneath and proximal to the grate 400.
  • the second portion of flue gas 272 may be provided through second duct 372 using a fan such as the first air fan 111.
  • a second air fan (not shown) may be used in lieu of, or in conjunction with the first air fan 111.
  • an additional gas 275 such as ambient air may be drawn in through a valve 112 or damper in cooperation with the first air fan 111, and added to the second portion of flue gas 272 to adjust or control the flowrate and oxygen content of the second portion of flue gas 272 delivered to fluidize the second portion of fuel 122 on the bed 440.
  • the temperature, gas velocity, and chemical composition of the fluidizing gas (i.e., the second portion of flue gas 272) for the fuel (i.e., the second portion of fuel 122) above the grate 400 can be controlled.
  • the second portion of fuel 122 is then conveyed to a mill or pulverizer 800 to be milled (i.e., to mechanically reduce the particulate size of the fuel 122), and thereafter re-introduced into the furnace 250 to be combusted therein.
  • the second portion of fuel 122 is conveyed out of the furnace 250 to the pulverizer by third conveyor 256, which may be a pressurized duct.
  • the third conveyor 256 may alternatively include a conventional mechanical belt-type conveyor, or a chute.
  • the second portion of fuel 122 may be conveyed via the third conveyer 256 to a dryer device 284 (FIG. 4), such as a conventional carbon separator and/or a heat exchanger, for further optimization (i.e., reduction) of moisture content and ash removal, prior to conveyance to, and sizing by, the pulverizer 800.
  • a dryer device 284 such as a conventional carbon separator and/or a heat exchanger
  • Still other embodiments may omit the dryer device 284 and convey the second portion of fuel 122 via the third conveyor 256 directly from the furnace 250 to the pulverizer 800 to be milled.
  • the second portion of fuel 122 is then conveyed to the furnace suspension firing system 102 to be burned.
  • the second portion of fuel 122 may be conveyed from pulverizer 800 and provided to first duct 272 for conveyance, along with the first portion of fuel 121, to the firing system 102.
  • the second portion of fuel 122 may be conveyed from pulverizer 800 (i.e., outside of the furnace 250) via a fourth conveyor 373. to the firing system 102 (i.e., inside the furnace) separately from the first portion of fuel 121 in first duct 371.
  • the fourth conveyor 373 may include a pressurized channel or duct 373 arranged in fluid communication with the mill 800 to receive the second portion of fuel 122 therefrom utilizing the pressurized air blowing from the mill 800.
  • the fourth conveyor 373 may include a fourth duct 373 in fluid communication with a fan (not shown) such as a conventional secondary air fan to pressurize the air in the fourth duct 373 to cooperatively convey the second portion of fuel 122 from the mill 800 through the fourth duct 373 to the firing system 102 in furnace 250.
  • Still other embodiments may use any number of mechanical conveyors arranged to define the fourth conveyor 373 to convey the second portion of fuel 122 to the firing system 102 in the furnace 250. As depicted in Figure. 2, some embodiments may include a fourth conveyor 373 including any number of fourth ducts to convey the second portion of fuel 122 from the pulverizer 800 to the firing system 102.
  • the boiler 100 may be started as a conventional semi-suspension system.
  • the second portion of the flue gas 272 is recirculated, and a devolatilization and a drying of the second portion of fuel 122 on grate 400 is initiated.
  • the second portion of fuel 122 is then extracted from the furnace 250 with the preferred moisture content to be sized in pulverizer 800 (with a relatively low parasitic load due to the lower moisture content), and then re-injected in the furnace 250 through the suspension firing system 102.
  • the method includes at step 401 providing the particles of solid fuel to a sieve, at step 402 separating the solid fuel into a first portion of fuel and a second portion of fuel based on a size of the particles of the solid fuel, wherein the size of the particles in the first portion of fuel are smaller than a predetermined size, and the size of the fuel particles in the second portion of fuel are larger than a predetermined size, at step 403 directing a flue gas through a flue, at step 414 providing a first portion of the flue gas to a first fuel-dryer including a first duct in fluid communication with the flue, at step 415 conveying the first portion of fuel to the first duct, at step 416 drying the first portion of fuel therein the first duct, at 417 conveying the first portion of fuel through the first duct to the furnace, and at 418 combusting the first portion of fuel with firing system.
  • the method further includes at step 421 conveying the second portion of fuel to a second fuel dryer disposed within a lower portion of the furnace and conveying a second portion of the flue gas to the second fuel dryer portion, at 422 drying the second portion of fuel with the second fuel dryer portion, at step 423 conveying the second portion of fuel from the second fuel dryer portion within the furnace to a mill disposed outside of the furnace, at step 424 reducing the size of the particles of the second portion of fuel with the mill, at step 425 conveying the second portion of fuel from the mill to the furnace, and at step 427 combusting the second portion of fuel with firing system.
  • the second portion of the fuel 122 is fed to the boiler 250 on the grate 400 and exposed to a reduced atmosphere, for a predetermined residence time with low gas velocity such that contaminant matter is released from the fuel 122.
  • a technical effect of these embodiments is that biomass ash entrainment away from the grate 400 is limited by low gas velocities thus reducing the tendency for plugging or fouling downstream of the furnace 250.
  • a technical effect of the above described embodiments is that by re-circulating the flue gas, controlling the reducing environment in the lower section of the furnace, and suspension firing of dried fuel allows for a better control of NOx emissions.
  • the boiler includes a hybrid dryer with a residence time adapted to larger size, high moisture moist fuel particles.
  • a hybrid dryer with a residence time adapted to larger size, high moisture moist fuel particles.
  • the bed 440 formed on the grate 400 by a stream of the second fuel 122 may be operative to reduce emissions of the furnace 250 by facilitating the capture of contaminants (represented by dashed circles 700), e.g., NOx, SOx, one or more alkalis, one or more alkaline earth elements, other contaminant metals, and/or other elements and/or chemicals that may cause corrosion, fouling, slagging, greenhouse effects, acid rain or are otherwise desirable to prevent from being emitted into the atmosphere / environment.
  • the bed 440 may be fluidized by recycled flue gas, e.g., the second portion of the flue gas 272 via duct 372.
  • the heat from the furnace 250 and/or flue gas 272 cause the fuel 122 to generate char 702, ash 704 and the contaminants 700.
  • the fuel 122 is partially gasified and combusted within the bed 440.
  • embodiments of the present invention facilitate the capture of the contaminants 700 by the ash 704, and in turn the char 702, i.e., the portion of the fuel 122 that is eventually fired in the furnace 250, has significantly less contaminants than the fuel 122 before entering the bed 440, or, in some embodiments, no contaminants.
  • the one or more properties of the bed 440 may include: a flow rate of the flue gas 272 across the bed 440 which may range from about 0.05 ft/s to about 5.0 ft/s; an oxygen concentration of the flue gas 272 within the bed 440, which may range from about 0% volume to about 21% volume; a temperature of the flue gas 272 within the bed 440 which may range from about an ambient temperature, e.g., 70-80 °F, to about 600 °F; a height H of the bed 440 which may range from about 3 ft to about 60 ft; a length L of the bed 440 which may range from about 1 ft to about 500 ft; a width W (not shown as it is normal to the drawing sheet of FIG.
  • a residence time i.e., the amount of time the fuel 122 spends within the bed 440, which may range from about 1 s to about 2 hrs (depending on the fuel moisture and temperature content); and/or other properties of the bed 440 which effect the chemistry and/or stoichiometric conditions within the bed 440.
  • the composition i.e., the substances making up the bed 440 can be varied.
  • the furnace 250 may further include an injector/delivery device 708 that delivers/feeds additives to the bed 440 so as to change the chemical composition of the bed 440.
  • additives may include limestone (to control sulfur emissions), clays (to capture alkalis), recycled fuel ash, lime, and/or any other sorbent capable of capturing contaminants.
  • the furnace 250 and/or the encompassing facility may further include a carbon separator 706 disposed downstream of the bed 440 and operative to separate the char 702 from the ash 704 so that the char 702 can be fired in the furnace 250 and the ash 704 containing the contaminants can be disposed of and/or further processed.
  • a carbon separator 706 disposed downstream of the bed 440 and operative to separate the char 702 from the ash 704 so that the char 702 can be fired in the furnace 250 and the ash 704 containing the contaminants can be disposed of and/or further processed.
  • the grate 400 may function as a carbon separator by allowing the ash 704 to fall down from the bed 440, while retaining the char 702 within the bed 440, with the ash 704 moving to receptacle 475 (FIG. 5) via outlet 410.
  • the char 702 may be sent to the mill 800 (FIG. 5) for processing before being fired in the furnace 250.
  • a controller 710 may monitor the chemistry of the bed 440 via one or more sensors 712 and adjust the properties of the bed 440, as discussed above, to optimize the capture of the contaminants 700 (FIG. 6).
  • the furnace 250, boiler 100 and/or encompassing power plant 90 may include the necessary electronics, software, memory, storage, databases, firmware, logic/state machines, microprocessors, communication links, displays or other visual or audio user interfaces, printing devices, and any other input/output interfaces to perform the functions described herein and/or to achieve the results described herein, which may be accomplished in real-time.
  • the controller 710 may include at least one processor and system memory / data storage structures, which may include random access memory (RAM) and read-only memory (ROM).
  • the at least one processor of the controller 710 may include one or more conventional microprocessors and one or more supplementary co-processors such as math co-processors or the like.
  • the data storage structures discussed herein may include an appropriate combination of magnetic, optical and/or semiconductor memory, and may include, for example, RAM, ROM, flash drive, an optical disc such as a compact disc and/or a hard disk or drive.
  • a software application that adapts the controller to perform the methods disclosed herein may be read into a main memory of the at least one processor from a computer- readable medium.
  • the term “computer-readable medium,” as used herein, refers to any medium that provides or participates in providing instructions to the at least one processor of the controller 710 (or any other processor of a device described herein) for execution. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media.
  • Non-volatile media include, for example, optical, magnetic, or opto-magnetic disks, such as memory.
  • Volatile media include dynamic random-access memory (DRAM), which typically constitutes the main memory.
  • Computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, a RAM, a PROM, an EPROM or EEPROM (electronically erasable programmable read-only memory), a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read.
  • a method for reducing the emission of contaminants by a furnace includes forming a bed from a stream of fuel within the furnace; fluidizing the bed with flue gas from the furnace; and heating the fuel within the bed so as to generate char, ash and contaminants.
  • the method further includes capturing the contaminants via the ash.
  • the contaminants are NOx, SOx, one or more alkalis, and/or one or more alkaline earth elements.
  • the method further includes adjusting at least one property of the bed.
  • the at least one property is: a flow rate of the flue gas across the bed; an oxygen concentration of the flue gas within the bed; a temperature of the flue gas within the bed; a height of the bed; and/or a residence time of the bed.
  • the at least one property is a flow rate of the flue gas across the bed and is adjusted to be within the range of about 0.05 ft/s to about 5.0 ft/s.
  • the at least one property is a temperature of the flue gas within the bed and is adjusted to be within about 70 °F to about 600 °F. In certain embodiments, the at least one property is a height of the bed and is adjusted to be between about 3 ft to about 60 ft. In certain embodiments, the at least one property is a residence time of the bed and is adjusted to be between about 1 s to about 2 hrs. In certain embodiments, the method further includes separating the char from the ash via a carbon separator.
  • the furnace includes a grate operative to form a bed from a stream of fuel, and a conduit operative to fluidize the bed with a flue gas generated by the furnace.
  • the bed facilitates: generation of char, ash and contaminants from the fuel; and capture of the contaminants by the ash.
  • the contaminants include NOx, SOx, one or more alkalis, and/or one or more alkaline earth elements.
  • one or more properties of the bed are operative to maximize the capture of contaminants by the ash.
  • the flue gas has a flow rate across the bed of about 0.05 ft/s to about 5 ft/s.
  • a temperature of the flue gas within the bed is between about 70 °F to about 600 °F. In certain embodiments, the bed has a height of between about 3 ft to about 5 ft. In certain embodiments, the bed has a residence time of between about 1 s to about 2 hrs.
  • the furnace includes a delivery device that feeds an additive to the bed. In certain embodiments, the furnace further includes a carbon separator operative to separate the char from the ash. In certain embodiments, the furnace further includes a mill operative to processes the char.
  • Non-transitory computer readable medium including instructions.
  • the instructions adapt at least one processor to: adjust at least one property of a bed formed by a stream of fuel within a furnace to facilitate: generation of char, ash and contaminants from the fuel; and capture of the contaminants by the ash.
  • some embodiments of the present invention may provide for improved emission reductions over traditional contaminant capture systems and approaches.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Combustion Of Fluid Fuel (AREA)
  • Incineration Of Waste (AREA)

Abstract

L'invention concerne un procédé de réduction de l'émission de contaminants par un four. Le procédé consiste à former un lit à partir d'un flux de combustible à l'intérieur du four; à fluidiser le lit avec un gaz de combustion provenant du four ; et à chauffer le combustible à l'intérieur du lit de façon à générer un produit de carbonisation, des cendres et des contaminants. Le procédé comprend en outre la capture des contaminants par l'intermédiaire des cendres.
EP20764232.3A 2019-08-22 2020-08-14 Chaudière-séchoir hybride et procédé associé Pending EP4018124A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16/548,167 US11142717B2 (en) 2019-03-22 2019-08-22 Hybrid boiler-dryer and method
PCT/US2020/046312 WO2021034637A1 (fr) 2019-08-22 2020-08-14 Chaudière-séchoir hybride et procédé associé

Publications (1)

Publication Number Publication Date
EP4018124A1 true EP4018124A1 (fr) 2022-06-29

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Application Number Title Priority Date Filing Date
EP20764232.3A Pending EP4018124A1 (fr) 2019-08-22 2020-08-14 Chaudière-séchoir hybride et procédé associé

Country Status (6)

Country Link
EP (1) EP4018124A1 (fr)
JP (1) JP2022545772A (fr)
CN (1) CN114270101A (fr)
TW (1) TWI837404B (fr)
WO (1) WO2021034637A1 (fr)
ZA (1) ZA202201710B (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3546465A1 (de) * 1985-11-02 1987-05-14 Helmut Kohler Verfahren und anordnung zum betrieb eines verbrennungskraftwerkes
JPH01210795A (ja) * 1988-02-18 1989-08-24 Ishikawajima Harima Heavy Ind Co Ltd 粉体燃焼床及び循環流動床燃焼装置
DE59203618D1 (de) * 1991-02-26 1995-10-19 Oberoesterr Ferngas Verfahren und Vorrichtung zum Verbrennen von stückigen, biogenen Brennstoffen.
FI120162B (fi) * 2005-02-17 2009-07-15 Foster Wheeler Energia Oy Leijupetikattilalaitos ja menetelmä rikkipitoisen polttoaineen polttamiseksi leijupetikattilalaitoksessa
TWI435034B (zh) * 2009-09-18 2014-04-21 Ind Tech Res Inst 流體化床燃燒爐溫度控制方法
CN103697466A (zh) * 2013-12-20 2014-04-02 哈尔滨锅炉厂有限责任公司 带烟气再循环旁路的循环流化床锅炉及nox排放方法

Also Published As

Publication number Publication date
JP2022545772A (ja) 2022-10-31
TW202108231A (zh) 2021-03-01
WO2021034637A1 (fr) 2021-02-25
TWI837404B (zh) 2024-04-01
CN114270101A (zh) 2022-04-01
ZA202201710B (en) 2022-10-26

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