Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/44—Details; Accessories
  • F23G5/46—Recuperation of heat
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B31/00—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus
  • F22B31/04—Heat supply by installation of two or more combustion apparatus, e.g. of separate combustion apparatus for the boiler and the superheater respectively
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/08—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating
  • F23G5/14—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/44—Details; Accessories
  • F23G5/48—Preventing corrosion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2202/00—Combustion
  • F23G2202/10—Combustion in two or more stages
  • F23G2202/103—Combustion in two or more stages in separate chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2202/00—Combustion
  • F23G2202/10—Combustion in two or more stages
  • F23G2202/104—Combustion in two or more stages with ash melting stage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2202/00—Combustion
  • F23G2202/10—Combustion in two or more stages
  • F23G2202/105—Combustion in two or more stages with waste supply in stages
• • 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
• • 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

Definitions

• a boiler producing steam from flue gases with high electrical efficiency and improved slag quality is provided.
• the invention relates to a boiler drying, igniting and combusting refuse and producing steam by heat exchange with flue gases. Subsequently, the steam is utilised to produce electricity.
• the refuse to be burnt can be any mixture of household refuse, bark, industrial waste and hospital refuse and other kinds of waste.
• US patent no. 6,269,754 discloses a steam generator for superheated steam for incineration plants with corrosive flue gases. It essentially comprises a radiation section and a convection section, having at least one superheater and having plates arranged on the inside of a wall of the radiation section, a space is being provided between the plates and the wall of the radiation section. At least a part of the superheater is being arranged as a wall superheater in the space in the radiation section.
• This space contains a less-corrosive gaseous atmosphere, which is at a higher pressure than the pressure of the gases in the combustion chamber.
• EP 0536268 B1 - from the applicant - discloses a method and apparatus for incinerating different kinds of solid and possibly liquid waste material.
• Solid and possibly liquid waste material is incinerated by a) partial combustion on the stepped grates of the solid waste material, the latter being delivered to a rotary kiln at such a high temperature that a liquid slag is formed at the inlet of the rotary kiln, b) possibly adding liquid waste material to the solid waste material being incinerated on the stepped grates, and c) collecting the ash products from the combustion process, such as grate screenings, boiler ash, fly ash, and residual products from flue-gas cleaning, and returning these products to the input end of the rotary kiln, at which input end these products are introduced into the liquid slag.
• the slag, fly ash and other harmful residual products from the combustion process are fused into a glass-like mass, from which salts and heavy metals cannot be leached out.
• EP 0536268 B1 does not provide for an optimised, electrical efficient output from the incineration of the solid and liquid waste material.
• the boiler comprises a reactor, positioned downstream of the moving bed furnace and possibly co-fired with firing a secondary fuel, for generating a less-corrosive gas flow and an end superheater located in the flow of said less- corrosive gas.
• the boiler dries, ignites and combusts refuse and produces steam by heat exchange with flue gases.
• the invention has the advantages that the lifetime of the end superheater of the boiler is increased and that the boiler also provides a high and efficient electrical power output due to the increased steam temperature in the end superheater.
• end superheater can be applied at a higher temperature when subjected to cleaner gases, i.e. less-corrosive gas and ash particles.
• fig. 1 shows an embodiment of the boiler using a reactor in combination with a burner applied to generate a non-corrosive gas
• fig. 2 shows an embodiment of the boiler using a reactor in combination with a burner applied to generate a non-corrosive gas with a separator element.
• the terms “superheater” or “end superheater” refers to a device that heats the steam generated by the boiler further, thereby increasing the thermal energy in the steam and decreasing the likelihood that said steam condenses.
• Steam, which has been superheated is logically known as superheated steam; conversely non-superheated steam is called saturated steam or wet steam. It is important to avoid the latter steam and thus primarily to use the superheated steam.
• this latter steam is fed into a steam turbine driving a generator, it will provide a high and efficient electrical power output, especially if the temperature and the pressure of the steam are sufficiently high.
• Bottom ash In general bottom ash is called slag.
• Bottom ash or slag is defined as the ash removed from the bottom part of the combustion zone of the boiler. Ashes are defined as the residual products from the combustion process.
• Figure 1 shows an embodiment of the boiler using a reactor in combination with a burner applied to generate a less-corrosive gas.
• the boiler (1 ) dries, ignites and combusts refuse.
• a gaseous atmosphere i.e. flue gases (3), is in the first place the result of incineration of refuse (9).
• the reactor (16) can be a sintering reactor, a rotary kiln, a fluidised bed or a spouted bed.
• the reactor sinters the bottom ash such that the leaching of heavy metals is reduced and the possibilities of utilising the bottom ash are improved.
• the sintering reactor is a reactor that heats the ash/slag so that leaching properties are improved. This means that the leaching of heavy metals from the ash/slag is re- prised.
• Said reactor (16) in general burns the refuse and turns it into slag and/or ash.
• the refuse to be burnt can be any mixtures of household refuse, bark, industrial waste and hospital refuse and other kinds of waste. Typically the refuse is supplied to the reactor
• the grates can be combined with one or more conveyors.
• the reactor is located - in the direction of the flow of the refuse - after the grate arrangement (21 ).
• a corrosive gas flow is the result in the pre-process, and conversely at reference numeral 6, a less-corrosive gas flow is the result in the post-process.
• the less-corrosive gas flow is the output from said reactor (16), possibly fired with a fuel (18), typically a secondary fuel (18).
• the secondary fuel is selected to develop flue gases that are less corrosive than the flue gases from said refuse or waste.
• the reactor is fired from the left-hand side with a secondary fuel (18).
• the firing follows the direction of the transport of refuse in the reactor, and as a result the less-corrosive gas flow as the output from said reactor is co-current, as indicated with the arrow 6.
• the firing of the reactor can take place by means of a burner (19), which can be fired with said secondary fuel (18), i.e. the burner can be fired with any combination of oil, gas, coal, biomass, air and a selected waste or refuse fraction.
• a burner (19) which can be fired with said secondary fuel (18), i.e. the burner can be fired with any combination of oil, gas, coal, biomass, air and a selected waste or refuse fraction.
• Said firing may take place by means of a burner (19) and/or take place in the reactor.
• the burner can be a suspension burner, possibly supplied with coal or a gas, or an oil burner, etc.
• the fuel and air injection into the reactor inlet comes via a separate housing/chute, which is separated from the corrosive flue gas (7).
• the reactor Since the reactor is fired, it reaches a higher temperature as compared to a reactor with no firing. This heat is needed to burn out the volatiles and to sinter the waste slag, trace and heavy metal species.
• This can be considered as a post-treatment process, i.e. the boiler or waste incinerator is combined with the reactor.
• the final ash and/or slag from the reactor is - due to its low content of leachable trace and heavy metal species, such as one or more of leachable Pb, As, Cd, Cu, Zn, Ni and Zn well-suited for reuse in road construction, etc and/or for disposal. Accordingly, environmental harm from ash and slag are minimised.
• the ash and/or slag is provided from the reactor by means of a bottom ash or slag removal device, which e.g. is a water filled through a piston pusher or belt conveyor.
• an integrated bottom ash treatment and improved electrical plant efficiency may be obtained by the concepts shown in the figure. It is thus advantageous to combine the high-efficient grate firing of e.g. refuse, such as municipal solid waste, with a post- treatment of the bottom ash (by means of the reactor) in a single plant, so that the final bottom-ash and/or slag produced will fulfil the current environmental and technical restrictions necessary for reuse, and at the same time this integrated post-treatment provides a less-corrosive flue gas (6), which can be applied to increase the end super- heater (8) steam temperature and thereby the electrical efficiency of the waste-fired boiler of the plant.
• the total process is integrated, energy-efficient and contained within a single plant without the need for transporting, storing, and subsequent handling/treatment of the bottom ash and/or slag from the grate in another plant.
• the electrical efficiency of the waste incineration plant is improved significantly due to the generation of the less-corrosive flue gas (6), which will allow higher steam temperatures (around 500 degrees Celsius) at the outlet 8b of the end superheater (8). Furthermore, it makes it possible to dispose of massive amounts of bottom ash and slag from waste incineration due to fixation of otherwise leachable trace and heavy metal fractions.
• Said less-corrosive gas is essentially free from corrosive components, such as Cl, K, Na, Zn, Pb, whereas the corrosive gas comprises corrosive components, e.g. comprises one or more of Cl, K, Na, Zn and Pb.
• less-corrosive gas can be understood as gases that provide less corrosion on the end superheater.
• Figure 2 shows an embodiment of the boiler using a reactor in combination with a burner (19) applied to generate a less-corrosive gas with a separator element.
• the reactor is fired from the right-hand side with a secondary fuel (18).
• the firing does not follow the direction of the transport of refuse in the reactor, and as a result the less-corrosive gas flow as the output from said reactor is counter current, as indicated with the arrow 6.
• the reactor is located at the end of the transportation direction of the refuse, which is discharged directly from the grate into the reactor.
• the firing of the reactor can take place by means of a burner (19), which can be fired with said secondary fuel (18), i.e. the burner can be fired with any combination of oil, gas, coal, biomass, air and a selected waste or refuse fraction.
• said secondary fuel in addition, or as an alternative, is supplied directly to the reactor instead. Since the reactor is fired, it reaches a higher temperature as compared to a reactor with no firing. This heat is needed to burn out the volatiles and to sinter the waste slag, trace and heavy metal species. This can be considered as a post-treatment process, i.e. the boiler or waste incinerator is combined with the reactor.
• the final ash and/or slag from the reactor is - due to its low content of leachable trace and heavy metal species, such as one or more of Pb, As, Cd, Cu, Zn, Ni and Zn - well- suited for reuse in road construction, etc and/or for disposal. Accordingly, environmental harm from ash and slag is minimised.
• a separation is provided to maintain separation of the gases, i.e. in order to protect the end superheater (8) from the corrosive gases (7), whereby it is mainly subjected to the non-corrosive gases (6).
• Said separa- tion of the flue gases (3) is maintained by means of a separator element denoted with reference numeral 4.
• This element could in an exemplary embodiment be provided as a plate (4a) or in the form of a wall (4b).
• the plate (4a) is typically a water filled boiler tube panel extending from one boiler side wall, typically also a water filled boiler tube panel, to the other boiler side wall, and the plate is suspended on said side walls.
• the plate may be corrosion-protected on the surfaces by e.g. high-alloy Cr-Ni overlay welding or by essentially tight refractory materials.
• the wall (4b) is typically a reinforced brick or cast refractory wall extending from the one boiler sidewall to the other boiler sidewalk
• the reinforcement may be hollow, allowing for passage of a cooling medium being e.g. a liquid, a vapour, a gas or air.
• the separator element could in another exemplary embodiment be provided as a channel, i.e. said plate (4a) and wall (4b) could in various combinations be used to form the channel.
• the channel could also have a tubular shape.
• the separator element is adapted to be suspendable on or from the walls of the boiler.
• the separator element may be a plate, a wall or channel able to pivot at the top in bearings suspended on the opposite boiler side walls and e.g. being able to move and fixate in different positions forwards/backwards at the bottom onto the boiler side walls.
• the steam (2) at between 300 and 450 degrees Celsius, after leaving said one or more superheaters, is fed, by means of one or more pipes, to an inlet (8a) of an end superheater (8), through which this steam (2) is heated, resulting in a temperature increase of between 25 and 200 degrees Celsius.
• This warmer steam (2a) i.e. the steam with the increased temperature
• a steam turbine (14) e.g. supplied from an outlet (8b) of the end superheater (8) to a steam turbine (14).
• this steam (2a) can be utilised to produce electricity.
• said steam can be fed by means of piping from said outlet into the steam turbine (14), which drives a generator (15), from which generator electrical power then can be generated.
• warmer steam (2a) is the output from the boiler, i.e. the output from the end superheater, the boiler accordingly also provides high power output efficiency. This is, of course, higher than if steam (2) at between 300 and 450 Celsius was the output from the boiler.
• the heating of the steam in said end superheater provides the high electrical power and high efficiency output.
• said end superheater (8) is located in proximity to said separator element (4), e.g. said plate, wall or into the channel, and in all cases in the flow (6) of said less-corrosive gas. It is thus an advantage that the end superheater is less subject to corrosion.
• the invention therefore has the advantages that the lifetime of the end superheater is increased and that the boiler provides a high electrical power efficiency.
• the boiler further comprises a blow unit (12).
• This is adapted to - by blowing secondary air - effectively mix said less-cor- rosive gas (6) with said corrosive gas (7), whereby said mix can be effectively burnt out before it reaches the top zone (13) of the boiler.
• the boiler is provided with an Industrial Draught fan, which sucks the gases, i.e. flue gases, the less-corrosive and the corrosive gases through the boiler. Additionally, combustion air can be blown in under the grate arrangement (21 ).

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
• Gasification And Melting Of Waste (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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ID=37745895

Family Applications (1)

Country Status (8)

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Citations (6)

Family Cites Families (20)

• 2006
  • 2006-09-29 CN CN2006800359997A patent/CN101287950B/zh not_active Expired - Fee Related
  • 2006-09-29 KR KR1020087009450A patent/KR101029906B1/ko not_active IP Right Cessation
  • 2006-09-29 CA CA2624054A patent/CA2624054C/en not_active Expired - Fee Related
  • 2006-09-29 US US12/067,968 patent/US20090050076A1/en not_active Abandoned
  • 2006-09-29 EP EP06809447A patent/EP1934526A1/en not_active Withdrawn
  • 2006-09-29 WO PCT/IB2006/053563 patent/WO2007036914A1/en active Application Filing
  • 2006-09-29 JP JP2008532967A patent/JP5053279B2/ja not_active Expired - Fee Related
• 2008
  • 2008-03-31 NO NO20081542A patent/NO20081542L/no not_active Application Discontinuation

Patent Citations (6)

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