EP4303488A1 - Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus - Google Patents
Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus Download PDFInfo
- Publication number
- EP4303488A1 EP4303488A1 EP22183389.0A EP22183389A EP4303488A1 EP 4303488 A1 EP4303488 A1 EP 4303488A1 EP 22183389 A EP22183389 A EP 22183389A EP 4303488 A1 EP4303488 A1 EP 4303488A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ammonia
- fluidized bed
- fluidizing
- reaction chamber
- carbonaceous fuel
- 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.)
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- 239000000446 fuel Substances 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000006243 chemical reaction Methods 0.000 claims abstract description 73
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 35
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000001301 oxygen Substances 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 27
- 238000002485 combustion reaction Methods 0.000 claims abstract description 23
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 173
- 229910021529 ammonia Inorganic materials 0.000 claims description 86
- 239000007789 gas Substances 0.000 claims description 28
- 238000002347 injection Methods 0.000 claims description 18
- 239000007924 injection Substances 0.000 claims description 18
- 239000007788 liquid Substances 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 6
- 230000003068 static effect Effects 0.000 claims description 6
- 239000004449 solid propellant Substances 0.000 claims description 5
- 239000002028 Biomass Substances 0.000 claims description 3
- 239000003245 coal Substances 0.000 claims description 3
- 239000013618 particulate matter Substances 0.000 description 12
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000003546 flue gas Substances 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 3
- 239000011449 brick Substances 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000008570 general process Effects 0.000 description 1
- 239000013529 heat transfer fluid Substances 0.000 description 1
- 238000010327 methods by industry Methods 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
Images
Classifications
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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
- F23C10/00—Fluidised bed combustion apparatus
-
- 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
- F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J7/00—Arrangement of devices for supplying chemicals to fire
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2203/00—Furnace arrangements
- F23G2203/50—Fluidised bed furnace
Definitions
- the present invention generally relates to a fluidized bed reactor and in particular to a fluidized apparatus comprising a fluidized bed reactor as well as to a method for operating such a fluidized bed reactor.
- a fluidized bed apparatus typically comprises a fluidized bed reactor, which walls can be made of tubes, through which water runs, wherein said tubes are either welded directly to each other to provide a wall structure or with fins/ribs between parallel running tube sections.
- the wall of the fluidized bed reactor may also be made of bricks or bricks in combination with tubes.
- the fluidized bed reactor comprises a reaction chamber for particulate and/or liquid matter, wherein the reaction chamber has at least one particulate matter inlet for the particulate matter and at least one primary particulate matter outlet for the particulate matter.
- the fluidized bed reactor may further comprise a fluidizing grate as part of a fluidizing bottom at the bottom of the reaction chamber, wherein the fluidizing grate has multiple openings for an operating fluid to fluidize particulate matter above the fluidizing grate within the reaction chamber.
- the multiple openings may be embodied by multiple nozzles, wherein each nozzle may have multiple openings.
- the reaction chamber of such a fluidized bed reactor has at least one operating fluid outlet at its upper end, wherein said operating fluid outlet allows a mixture of gases and solid particles (hereinafter called particulate matter) exhausted from the reaction chamber to flow into at least one separator.
- particulate matter a mixture of gases and solid particles
- the separator serves to disengage the gases and particulate matter. Thereafter the separated reaction gases and the particulate matter are treated separately. The particulate matter may be directly returned into the reaction chamber.
- the general process engineering of this type of a fluidized bed apparatus is more or less defined and includes:
- the fluidized bed can be embodied as stationary, bubbling or circulating fluidized bed.
- the present invention relates to a method for combusting carbonaceous fuel in a fluidized bed reactor, wherein at least one carbonaceous fuel is provided to the reaction chamber of the fluidized bed reactor.
- a respective fluidized bed apparatus comprises a fluidized bed reactor, which has a reaction chamber, a fluidizing bottom at the bottom of the reaction chamber and at least one carbonaceous fuel supply above the fluidizing bottom. Furthermore, the fluidized bed apparatus comprises at least one source for a carbonaceous fuel being connected to the carbonaceous fuel supply and at least one fluidizing agent source being connected to the fluidizing bottom, wherein at least one fluidizing agent source is configured to supply a gas comprising gaseous oxygen.
- the carbonaceous fuel may be a solid fuel, which is provided as the above described particulate matter to the reaction chamber.
- the carbonaceous solid fuel may be coal or biomass.
- a liquid carbonaceous fuel may be provided to the reaction chamber.
- oil may be provided as liquid carbonaceous fuel to the reaction chamber.
- a fluidizing agent also referred to as operating gas
- gaseous oxygen is provided at the bottom of the fluidized bed chamber, so that the carbonaceous fuel and in particular the solid carbonaceous fuel is fluidized by the provided fluidizing agent.
- an ignition device may be arranged within the reaction chamber.
- the oxygen comprising gas is in particular air, which is supplied as primary air into the reaction chamber at the bottom of the reaction chamber through the fluidizing bottom.
- the fluidizing agent source may be the surrounding atmosphere.
- solid carbonaceous fuel is provided to the reaction chamber, whereas liquid carbonaceous fuel may be added as auxiliary carbonaceous fuel.
- the combustion of carbonaceous fuel within a reaction chamber of a fluidized bed reactor is generally known, for example from EP 0 495 296 A2 .
- EP 0 280 016 A2 discloses a device for introducing a gaseous medium into a reaction chamber of a fluidized bed reactor.
- the disclosed device for introducing a gaseous medium can be arranged at multiple locations within the reaction chamber. It is disclosed, that the device is arranged at the bottom of the reaction chamber or above the bottom of the reaction chamber, so that the outlets of the device would be arranged within or above the fluidized bed during operation. Accordingly, the device disclosed in EP 0 280 016 can be used as fluidizing bottom or as a device for introducing gaseous medium within or above the fluidized bed.
- EP 0 280 016 A2 also discloses that ammonia can be supplied with the device. But it is not disclosed, at which location ammonia is supplied by the device. In light of the general technical knowledge it has to be assumed that the device is used to add ammonia to the flue gases, so that a selective non-catalytic reaction occurs.
- a solution for this object is provided with a fluidized bed reactor and a method for combusting carbonaceous fuel in a fluidized bed reactor according to the features of the respective independent claim.
- Further solutions and preferred embodiments of the fluidized bed reactor and the method are subject matter of the dependent claims and the above and below description, wherein single features of the preferred embodiments can be combined with each other in a technically meaningful manner.
- Features disclosed with regard to the method can be applied to the fluidized bed reactor and vice versa.
- the fluidized bed apparatus comprises at least one ammonia source, which is connected to a bottom of the reaction chamber.
- the present invention suggests providing thermal energy to the reaction chamber, in which carbonaceous fuel is combusted, by combusting ammonia, wherein the thermal energy of the combustion of the carbonaceous fuel and the thermal energy of the combustion of ammonia can be withdrawn by the heat transfer elements of the fluidized bed reactor.
- the combustion of ammonia does not produce additional CO 2 .
- the invention can be implemented in existing fluidized bed apparatuses with only little effort.
- the thermal energy can either be produced directly in the reaction chamber by combusting ammonia within the reaction chamber or by combusting ammonia in order to heat up a medium which is supplied into the reaction chamber.
- ammonia is provided at the bottom of the reaction chamber.
- the at least one ammonia source is connected to the fluidizing bottom.
- Ammonia is added to the fluidizing bed, in which the combustion reaction of the carbonaceous fuel with the gaseous oxygen occurs, so that ammonia itself can react with the gaseous oxygen in a combustion reaction in an exothermic manner.
- ammonia provided from the bottom of the reaction chamber can be combusted in a fluidized bed reactor together with the carbonaceous fuel.
- the ignition temperature for the combustion of ammonia within the fluidized bed is provided by the combustion process of the carbonaceous fuel.
- ammonia By combusting ammonia, preferably within the fluidized bed of the reaction chamber, the emission of CO 2 can be reduced without reducing the thermal energy generated, as ammonia may partly replace the carbonaceous fuel. Ammonia may be produced in times of a surplus of electrical energy of renewable energy sources. On the other hand, ammonia can be combusted on demand with the inventive method and apparatus. This way, a surplus of electrical energy may be chemically stored in the ammonia and used by the method of the present invention.
- Ammonia may be added together with the gas comprising gaseous oxygen at the bottom of the reaction chamber, so that ammonia is part of the fluidizing agent.
- the fluidizing agent source may be connected to a duct leading to the fluidizing bottom, wherein an injection apparatus is arranged within the duct and wherein the injection apparatus is connected to the ammonia source, so that ammonia is injected in the oxygen comprising gas supplied from the first fluidizing agent source through the duct.
- ammonia is part of the fluidizing agent provided through the fluidizing bottom into the reaction chamber.
- the injection apparatus may comprise at least one injector and at least one static mixer, wherein the at least one static mixer is arranged within the duct downstream of the at least one injector.
- ammonia injected through the injector into the duct is blended with the oxygen comprising gas, so that an evenly distributed mixture of the oxygen comprising gas and ammonia is supplied into the reaction chamber via the fluidizing bottom.
- the injection apparatus comprises at least one pipe arranged within the duct, wherein at least one pipe has multiple injection openings through which ammonia is injected into the duct.
- ammonia can be injected at multiple locations (at least 20 or at least 50) over the cross section of the duct.
- an evenly distributed mixture of the oxygen comprising gas and the gaseous ammonia is provided to the reaction chamber via the fluidizing bottom.
- ammonia may be introduced at the bottom of the reaction chamber in close vicinity of the location, at which the fluidizing agent is introduced into the reaction chamber at the bottom of the reaction chamber.
- the fluidizing bottom may comprise multiple first openings and multiple second openings, wherein the multiple first openings are connected to the at least one first fluidizing agent source and wherein the multiple second openings are connected to the ammonia source.
- the multiple openings of the fluidizing bottom may be embodied by multiple nozzles, which each may comprise at least one or more openings.
- the openings of the fluidizing bottom may be embodied in pipes, so that the fluidizing agent and ammonia are provided through a pipe (system) to the bottom of the reaction chamber. It may also be possible that the multiple openings of the fluidizing bottom are embodied as a perforated plate. In each case a group of first multiple openings may be connected to the first fluidizing agent source and another group of multiple openings may be connected to the ammonia source, in case ammonia is not mixed with the oxygen comprising gas beforehand.
- ammonia is combusted outside the reaction chamber, wherein the thermal energy produced by the combustion of ammonia is supplied into the reaction chamber.
- the combustion gases of the ammonia combustion are used to heat up a medium, in particular the fluidizing agent, which is supplied into the reaction chamber.
- the fluidizing agent source may be connected to the duct leading to the fluidizing bottom, wherein a burner is arranged within the duct, wherein the burner is connected to the ammonia source so that combusted ammonia is added to the oxygen comprising gas supplied form the fluidizing agent source through the duct.
- the ammonia is preferably stored at a pressure in a respective vessel, at which at least part of the ammonia may be in the liquid phase. In this case, it is preferable that gaseous ammonia is withdrawn from the ammonia source and provided to the reaction chamber.
- ammonia in the liquid phase may be withdrawn from the ammonia source, in which case ammonia evaporates, when it is injected into the reaction chamber or into the duct leading to the reaction chamber.
- ammonia makes 2 % by volume to 30 % by volume of the whole volume of the gases provided at the bottom.
- the mass ratio of ammonia to carbonaceous fuel is between 0,05 and 0,5.
- the mass ratio of ammonia to carbonaceous fuel is between 0,1 and 0,25 and most preferably between 0,2 and 0,1. Accordingly, 5 % to 50 % by mass of the carbonaceous fuel may be replaced by ammonia to receive a similar heat output. Even if the carbonaceous fuel is not replaced by ammonia but ammonia is added to the combustion process at a constant mass supply of the carbonaceous fuel, the mass of the supplied ammonia may be between 5 % to 50 % of the mass of the supplied carbonaceous fuel.
- the fluidized bed apparatus shown in Figure 1 comprises a fluidized bed reactor 1, which has a reaction chamber 2, at which bottom a fluidizing bottom 3 is arranged.
- a duct 8 is connected to the fluidizing bottom 3, through which duct 8 an oxygen comprising gas from a fluidizing agent source 6 is supplied to the fluidizing bottom 3.
- An injection apparatus 9 is arranged within the duct 8.
- the injection apparatus 9 is connected to an ammonia source 7, so that ammonia can be injected into the duct 8 and into the oxygen comprising gas flowing towards the fluidizing bottom 3.
- the fluidized bed apparatus comprises two carbonaceous fuel sources 5, which are connected to respective carbonaceous fuel supplies 4 arranged above the fluidizing bottom.
- solid fuel such as coal or biomass may be provided from the carbonaceous fuel source 5 into the reaction chamber 2 via the upper carbonaceous fuel supply.
- oil as liquid carbonaceous fuel may be supplied from the carbonaceous fuel source 5 through the lower carbonaceous fuel supply 4.
- the fluidized bed apparatus further comprises a secondary air supply 15, with which secondary air may be supplied into the reaction chamber 2. Additionally, the fluidized bed apparatus comprises an ignition device 14, which is arranged within the reaction chamber 2.
- a separator 16 is arranged adjacent to the reaction chamber 2, wherein the separator 16 is connected via a return duct 17 to the reaction chamber 2 above the fluidizing bed 3.
- carbonaceous fuel is supplied from the carbonaceous fuel supply 4 into the reaction chamber 2, in which the carbonaceous fuel is fluidized by a gas mixture provided from duct 8 through the fluidizing bottom 3.
- the fluidizing agent provided through the duct 8 comprises an oxygen comprising gas from the fluidizing agent source 6 and ammonia from the ammonia source 7.
- the ignition device 14 is actuated.
- the carbonaceous fuel reacts with the oxygen and ammonia reacts with the oxygen in combustion processes. Accordingly, the thermal energy generated in the reaction chamber 2 is based on a combustion of the carbonaceous fuel and of ammonia. Secondary air may be added to the combustion process through the secondary air supply 15. As the combustion process is not solely based on the combustion of carbonaceous fuel, less carbon dioxide is exhausted.
- Solid particles leaving the reaction chamber 2 at the upper end are separated from the combustion gases 9in separator 16, whereas the separated solid particles are returned to the reaction chamber 2 via the return duct 17.
- the injection apparatus 9, with which ammonia is injected into the duct 8 may comprise multiple injectors 10, as depicted in Figure 2 .
- Each injector 10 has a single opening, through which ammonia is injected into the duct 8.
- a static mixer for each injector 10 is arranged downstream to the injector 10 within the duct 8. Thereby, ammonia is evenly mixed with the oxygen comprising gas.
- each pipe 12 comprises multiple openings 13 through which ammonia is injected into the duct 8. Accordingly, ammonia is evenly distributed injected into the duct 8 already at the plane of injection.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
The invention relates to a method for combusting carbonaceous fuel in a fluidized bed reactor (1), comprising the following steps:- Providing at least one carbonaceous fuel to a reaction chamber (2) of the fluidized bed reactor (1),- Providing a fluidizing agent at a bottom of the reaction chamber (2), thereby fluidizing the carbonaceous fuel, wherein the fluidizing agent comprises gaseous oxygen, wherein a combustion reaction of the carbonaceous fuel with the gaseous oxygen occurs.
Description
- The present invention generally relates to a fluidized bed reactor and in particular to a fluidized apparatus comprising a fluidized bed reactor as well as to a method for operating such a fluidized bed reactor. Hereinafter terms like "upper", "lower", "horizontal", "vertical", "inner" etc. always refer to a regular used position of the fluidized bed reactor. A fluidized bed apparatus typically comprises a fluidized bed reactor, which walls can be made of tubes, through which water runs, wherein said tubes are either welded directly to each other to provide a wall structure or with fins/ribs between parallel running tube sections. The wall of the fluidized bed reactor may also be made of bricks or bricks in combination with tubes.
- The fluidized bed reactor comprises a reaction chamber for particulate and/or liquid matter, wherein the reaction chamber has at least one particulate matter inlet for the particulate matter and at least one primary particulate matter outlet for the particulate matter. The fluidized bed reactor may further comprise a fluidizing grate as part of a fluidizing bottom at the bottom of the reaction chamber, wherein the fluidizing grate has multiple openings for an operating fluid to fluidize particulate matter above the fluidizing grate within the reaction chamber. The multiple openings may be embodied by multiple nozzles, wherein each nozzle may have multiple openings.
- Typically, the reaction chamber of such a fluidized bed reactor has at least one operating fluid outlet at its upper end, wherein said operating fluid outlet allows a mixture of gases and solid particles (hereinafter called particulate matter) exhausted from the reaction chamber to flow into at least one separator.
- The separator serves to disengage the gases and particulate matter. Thereafter the separated reaction gases and the particulate matter are treated separately. The particulate matter may be directly returned into the reaction chamber.
- The general design of a circulating fluidized bed apparatus and its components is disclosed in
EP 0 495 296 A2 . - The general process engineering of this type of a fluidized bed apparatus is more or less defined and includes:
- providing the particulate matter via an inlet opening into the reaction chamber,
- fluidizing the particulate matter by a (operating) gas, introduced under pressure via a fluidizing bottom, which may comprise respective nozzles and/or a grate in the grate area of the reaction chamber,
- eventually transferring the energy (heat) produced in the fluidized bed via heat transfer elements (in particular tubes through which a heat transfer fluid like water or steam flows), arranged in or adjacent to the reaction chamber or transferring the energy from the reaction gases having left the reaction chamber.
- Depending on the velocity of the provided operating fluid the fluidized bed can be embodied as stationary, bubbling or circulating fluidized bed.
- More specifically, the present invention relates to a method for combusting carbonaceous fuel in a fluidized bed reactor, wherein at least one carbonaceous fuel is provided to the reaction chamber of the fluidized bed reactor.
- Accordingly, a respective fluidized bed apparatus comprises a fluidized bed reactor, which has a reaction chamber, a fluidizing bottom at the bottom of the reaction chamber and at least one carbonaceous fuel supply above the fluidizing bottom. Furthermore, the fluidized bed apparatus comprises at least one source for a carbonaceous fuel being connected to the carbonaceous fuel supply and at least one fluidizing agent source being connected to the fluidizing bottom, wherein at least one fluidizing agent source is configured to supply a gas comprising gaseous oxygen.
- In particular, the carbonaceous fuel may be a solid fuel, which is provided as the above described particulate matter to the reaction chamber. For example, the carbonaceous solid fuel may be coal or biomass. Additionally, a liquid carbonaceous fuel may be provided to the reaction chamber. For example, oil may be provided as liquid carbonaceous fuel to the reaction chamber.
- In order that a combustion reaction of the carbonaceous fuel can occur, a fluidizing agent (also referred to as operating gas) comprising gaseous oxygen is provided at the bottom of the fluidized bed chamber, so that the carbonaceous fuel and in particular the solid carbonaceous fuel is fluidized by the provided fluidizing agent. In order that the combustion reaction starts, an ignition device may be arranged within the reaction chamber.
- The oxygen comprising gas is in particular air, which is supplied as primary air into the reaction chamber at the bottom of the reaction chamber through the fluidizing bottom. In this case, the fluidizing agent source may be the surrounding atmosphere.
- In a preferred embodiment, solid carbonaceous fuel is provided to the reaction chamber, whereas liquid carbonaceous fuel may be added as auxiliary carbonaceous fuel. The combustion of carbonaceous fuel within a reaction chamber of a fluidized bed reactor is generally known, for example from
EP 0 495 296 A2 . - It is also known to add gaseous ammonia to the flue gases of the combustion reaction in order to reduce the nitrogen oxide emission. This method is known as selective non-catalytic reduction (SNCR). In order that a selective non-catalytic reduction occurs, ammonia (or urea) is injected at locations, where the temperature of the flue gases is between 760 °C and 1090 °C. If ammonia would be injected to the flue gases at higher temperatures, additional nitrogen oxide would be produced.
-
EP 0 280 016 A2 discloses a device for introducing a gaseous medium into a reaction chamber of a fluidized bed reactor. The disclosed device for introducing a gaseous medium can be arranged at multiple locations within the reaction chamber. It is disclosed, that the device is arranged at the bottom of the reaction chamber or above the bottom of the reaction chamber, so that the outlets of the device would be arranged within or above the fluidized bed during operation. Accordingly, the device disclosed inEP 0 280 016 can be used as fluidizing bottom or as a device for introducing gaseous medium within or above the fluidized bed.EP 0 280 016 A2 also discloses that ammonia can be supplied with the device. But it is not disclosed, at which location ammonia is supplied by the device. In light of the general technical knowledge it has to be assumed that the device is used to add ammonia to the flue gases, so that a selective non-catalytic reaction occurs. - Against this background, it is an object of the present invention to provide a fluidized bed apparatus and a method for combusting carbonaceous fuel in a fluidized bed reactor, with which the CO2 emission can be reduced.
- A solution for this object is provided with a fluidized bed reactor and a method for combusting carbonaceous fuel in a fluidized bed reactor according to the features of the respective independent claim. Further solutions and preferred embodiments of the fluidized bed reactor and the method are subject matter of the dependent claims and the above and below description, wherein single features of the preferred embodiments can be combined with each other in a technically meaningful manner. Features disclosed with regard to the method can be applied to the fluidized bed reactor and vice versa.
- In particular, it is suggested that ammonia (NH3) is combusted to provide thermal energy to the reaction chamber. Accordingly, the fluidized bed apparatus comprises at least one ammonia source, which is connected to a bottom of the reaction chamber.
- With other words: The present invention suggests providing thermal energy to the reaction chamber, in which carbonaceous fuel is combusted, by combusting ammonia, wherein the thermal energy of the combustion of the carbonaceous fuel and the thermal energy of the combustion of ammonia can be withdrawn by the heat transfer elements of the fluidized bed reactor. The combustion of ammonia does not produce additional CO2. Furthermore, the invention can be implemented in existing fluidized bed apparatuses with only little effort. The thermal energy can either be produced directly in the reaction chamber by combusting ammonia within the reaction chamber or by combusting ammonia in order to heat up a medium which is supplied into the reaction chamber.
- In a preferred embodiment ammonia is provided at the bottom of the reaction chamber. Accordingly, the at least one ammonia source is connected to the fluidizing bottom. With other words: Ammonia is added to the fluidizing bed, in which the combustion reaction of the carbonaceous fuel with the gaseous oxygen occurs, so that ammonia itself can react with the gaseous oxygen in a combustion reaction in an exothermic manner. This way, ammonia provided from the bottom of the reaction chamber can be combusted in a fluidized bed reactor together with the carbonaceous fuel. In this regard, it is believed that the ignition temperature for the combustion of ammonia within the fluidized bed is provided by the combustion process of the carbonaceous fuel.
- By combusting ammonia, preferably within the fluidized bed of the reaction chamber, the emission of CO2 can be reduced without reducing the thermal energy generated, as ammonia may partly replace the carbonaceous fuel. Ammonia may be produced in times of a surplus of electrical energy of renewable energy sources. On the other hand, ammonia can be combusted on demand with the inventive method and apparatus. This way, a surplus of electrical energy may be chemically stored in the ammonia and used by the method of the present invention.
- Ammonia may be added together with the gas comprising gaseous oxygen at the bottom of the reaction chamber, so that ammonia is part of the fluidizing agent. For example, the fluidizing agent source may be connected to a duct leading to the fluidizing bottom, wherein an injection apparatus is arranged within the duct and wherein the injection apparatus is connected to the ammonia source, so that ammonia is injected in the oxygen comprising gas supplied from the first fluidizing agent source through the duct. In this case, ammonia is part of the fluidizing agent provided through the fluidizing bottom into the reaction chamber.
- In a specific embodiment, the injection apparatus may comprise at least one injector and at least one static mixer, wherein the at least one static mixer is arranged within the duct downstream of the at least one injector. In this configuration, ammonia injected through the injector into the duct is blended with the oxygen comprising gas, so that an evenly distributed mixture of the oxygen comprising gas and ammonia is supplied into the reaction chamber via the fluidizing bottom.
- In a further specific embodiment, the injection apparatus comprises at least one pipe arranged within the duct, wherein at least one pipe has multiple injection openings through which ammonia is injected into the duct. By using such an array-like arrangement with multiple (at least two, preferably at least five or at least ten) pipes arranged over the cross section of the duct, ammonia can be injected at multiple locations (at least 20 or at least 50) over the cross section of the duct. Also in this configuration, an evenly distributed mixture of the oxygen comprising gas and the gaseous ammonia is provided to the reaction chamber via the fluidizing bottom.
- Alternatively, ammonia may be introduced at the bottom of the reaction chamber in close vicinity of the location, at which the fluidizing agent is introduced into the reaction chamber at the bottom of the reaction chamber. For example, the fluidizing bottom may comprise multiple first openings and multiple second openings, wherein the multiple first openings are connected to the at least one first fluidizing agent source and wherein the multiple second openings are connected to the ammonia source.
- The multiple openings of the fluidizing bottom may be embodied by multiple nozzles, which each may comprise at least one or more openings.
- Alternatively, the openings of the fluidizing bottom may be embodied in pipes, so that the fluidizing agent and ammonia are provided through a pipe (system) to the bottom of the reaction chamber. It may also be possible that the multiple openings of the fluidizing bottom are embodied as a perforated plate. In each case a group of first multiple openings may be connected to the first fluidizing agent source and another group of multiple openings may be connected to the ammonia source, in case ammonia is not mixed with the oxygen comprising gas beforehand.
- In an alternative embodiment ammonia is combusted outside the reaction chamber, wherein the thermal energy produced by the combustion of ammonia is supplied into the reaction chamber. In particular, the combustion gases of the ammonia combustion are used to heat up a medium, in particular the fluidizing agent, which is supplied into the reaction chamber. For example, the fluidizing agent source may be connected to the duct leading to the fluidizing bottom, wherein a burner is arranged within the duct, wherein the burner is connected to the ammonia source so that combusted ammonia is added to the oxygen comprising gas supplied form the fluidizing agent source through the duct.
- The ammonia is preferably stored at a pressure in a respective vessel, at which at least part of the ammonia may be in the liquid phase. In this case, it is preferable that gaseous ammonia is withdrawn from the ammonia source and provided to the reaction chamber.
- Alternatively, ammonia in the liquid phase may be withdrawn from the ammonia source, in which case ammonia evaporates, when it is injected into the reaction chamber or into the duct leading to the reaction chamber.
- In a preferred embodiment and independent if the gaseous ammonia is provided in a mixture with the oxygen comprising gas as fluidizing agent or if ammonia is provided separately from the fluidizing agent at the bottom of the reaction chamber, ammonia makes 2 % by volume to 30 % by volume of the whole volume of the gases provided at the bottom. Preferably, 5 % by volume to 25 % by volume and most preferably 10 % by volume to 20 % by volume of the gases provided at the bottom of the fluidized bed chamber is ammonia.
- In an embodiment, the mass ratio of ammonia to carbonaceous fuel is between 0,05 and 0,5. Preferably, the mass ratio of ammonia to carbonaceous fuel is between 0,1 and 0,25 and most preferably between 0,2 and 0,1. Accordingly, 5 % to 50 % by mass of the carbonaceous fuel may be replaced by ammonia to receive a similar heat output. Even if the carbonaceous fuel is not replaced by ammonia but ammonia is added to the combustion process at a constant mass supply of the carbonaceous fuel, the mass of the supplied ammonia may be between 5 % to 50 % of the mass of the supplied carbonaceous fuel.
- The invention and the technical background will now be described with regard to the figures. The figures show schematically
- Figure 1:
- a fluidized bed apparatus with a duct leading to a fluidizing bottom,
- Figure 2:
- an embodiment of an injection apparatus arranged in the duct and
- Figure 3:
- a further embodiment of an injection apparatus arranged in the duct.
- The fluidized bed apparatus shown in
Figure 1 comprises a fluidized bed reactor 1, which has areaction chamber 2, at which bottom a fluidizingbottom 3 is arranged. - A
duct 8 is connected to thefluidizing bottom 3, through whichduct 8 an oxygen comprising gas from afluidizing agent source 6 is supplied to thefluidizing bottom 3. - An
injection apparatus 9 is arranged within theduct 8. Theinjection apparatus 9 is connected to anammonia source 7, so that ammonia can be injected into theduct 8 and into the oxygen comprising gas flowing towards the fluidizingbottom 3. - The fluidized bed apparatus comprises two carbonaceous fuel sources 5, which are connected to respective
carbonaceous fuel supplies 4 arranged above the fluidizing bottom. For example, solid fuel such as coal or biomass may be provided from the carbonaceous fuel source 5 into thereaction chamber 2 via the upper carbonaceous fuel supply. Furthermore, oil as liquid carbonaceous fuel may be supplied from the carbonaceous fuel source 5 through the lowercarbonaceous fuel supply 4. - The fluidized bed apparatus further comprises a
secondary air supply 15, with which secondary air may be supplied into thereaction chamber 2. Additionally, the fluidized bed apparatus comprises anignition device 14, which is arranged within thereaction chamber 2. - A
separator 16 is arranged adjacent to thereaction chamber 2, wherein theseparator 16 is connected via areturn duct 17 to thereaction chamber 2 above the fluidizingbed 3. - During operation, carbonaceous fuel is supplied from the
carbonaceous fuel supply 4 into thereaction chamber 2, in which the carbonaceous fuel is fluidized by a gas mixture provided fromduct 8 through the fluidizingbottom 3. The fluidizing agent provided through theduct 8 comprises an oxygen comprising gas from the fluidizingagent source 6 and ammonia from theammonia source 7. In order to start a combustion process, theignition device 14 is actuated. - When the combustion process is started, the carbonaceous fuel reacts with the oxygen and ammonia reacts with the oxygen in combustion processes. Accordingly, the thermal energy generated in the
reaction chamber 2 is based on a combustion of the carbonaceous fuel and of ammonia. Secondary air may be added to the combustion process through thesecondary air supply 15. As the combustion process is not solely based on the combustion of carbonaceous fuel, less carbon dioxide is exhausted. - Solid particles leaving the
reaction chamber 2 at the upper end are separated from the combustiongases 9in separator 16, whereas the separated solid particles are returned to thereaction chamber 2 via thereturn duct 17. - The
injection apparatus 9, with which ammonia is injected into theduct 8 may comprisemultiple injectors 10, as depicted inFigure 2 . Eachinjector 10 has a single opening, through which ammonia is injected into theduct 8. A static mixer for eachinjector 10 is arranged downstream to theinjector 10 within theduct 8. Thereby, ammonia is evenly mixed with the oxygen comprising gas. - In the embodiment according to
Figure 3 ,multiple pipes 12 are arranged beside each other within theduct 8, wherein eachpipe 12 comprisesmultiple openings 13 through which ammonia is injected into theduct 8. Accordingly, ammonia is evenly distributed injected into theduct 8 already at the plane of injection. -
- 1
- Fluidized bed reactor
- 2
- Reaction chamber
- 3
- Fluidizing bottom
- 4
- Carbonaceous fuel supply
- 5
- Carbonaceous fuel source
- 6
- Fluidizing agent source
- 7
- Ammonia source
- 8
- Duct
- 9
- Injection apparatus
- 10
- Injector
- 11
- Static mixer
- 12
- Pipe
- 13
- Injection opening
- 14
- Ignition device
- 15
- Secondary air supply
- 16
- Separator
- 17
- Return duct
Claims (15)
- Method for combusting carbonaceous fuel in a fluidized bed reactor (1), comprising the following steps:- Providing at least one carbonaceous fuel to a reaction chamber (2) of the fluidized bed reactor (1),- Providing a fluidizing agent at a bottom of the reaction chamber (2), thereby fluidizing the carbonaceous fuel, wherein the fluidizing agent comprises gaseous oxygen, wherein a combustion reaction of the carbonaceous fuel with the gaseous oxygen occurs,characterized in that
ammonia is combusted to provide thermal energy to the reaction chamber (2). - Method according to claim 1, wherein ammonia is provided at the bottom of the reaction chamber (2).
- Method according to claim 2, wherein a mixture of a gaseous oxygen comprising gas and gaseous ammonia is provided at the bottom of the reaction chamber as fluidizing agent.
- Method according to claim 2 or 3, wherein 2 Vol. % to 30 Vol. % of the gases provided at the bottom of the fluidized bed chamber is ammonia.
- Method according to one of the preceding claims, wherein the mass ratio of ammonia to carbonaceous fuel is between 0,05 and 0,5.
- Method according to claim 1, wherein ammonia is combusted to heat up the fluidizing agent.
- Method according to one of the preceding claims, wherein the carbonaceous fuel is a solid fuel and/or a liquid fuel.
- Method according to claim 7, wherein the solid fuel is coal or biomass.
- Method according to claim 7 or 8, wherein the liquid fuel is oil.
- Fluidized bed apparatus, comprising• a fluidized bed reactor (1), the fluidized bed reactor (1) having- a reaction chamber (2),- a fluidizing bottom (3) at the bottom of the reaction chamber (2),- at least one carbonaceous fuel supply (4) above the fluidizing bottom (3),• at least one source (5) for a carbonaceous fuel being connected to the carbonaceous fuel supply (4),• at least one fluidizing agent source (6) being connected to the fluidizing bottom (3), wherein at least one fluidizing agent source (6) is configured to supply a gas comprising gaseous oxygen,characterized in that
the fluidized bed apparatus comprises at least one ammonia source (7) being connected to a bottom of the reaction chamber (2), in particular to the fluidizing bottom (3). - Fluidized bed apparatus according to claim 10, wherein the fluidizing agent source (6) is connected to a duct (8) leading to the fluidizing bottom (3), wherein an injection apparatus (9) is arranged within the duct (8), wherein the injection apparatus (9) is connected to the ammonia source (6), so that ammonia is injected in the oxygen comprising gas supplied from the first fluidizing agent source (6) through the duct (8).
- Fluidized bed apparatus according to claim 11, wherein the injection apparatus (9) comprises at least one injector (10) and at least one static mixer (11), wherein the at least one static mixer (11) is arranged within the duct (8) downstream of the at least one injector (10).
- Fluidized bed apparatus according to claim 11, wherein the injection apparatus (9) comprises at least one pipe (12), one pipe having multiple injection openings (13), through which ammonia is injected into the duct (8).
- Fluidized bed apparatus according to claim 10, wherein the fluidizing agent source (6) is connected to a duct (8) leading to the fluidizing bottom (3), wherein a burner is arranged within the duct (8), wherein the burner is connected to the ammonia source (7) so that combusted ammonia is added to the oxygen comprising gas supplied form the fluidizing agent source (6) through the duct (8).
- Fluidized bed apparatus according to claim 10, wherein the fluidizing bottom (3) comprises multiple first openings and multiple second openings, wherein the multiple first openings are connected to the at least one fluidizing agent source (6) and wherein the multiple second openings are connected to the ammonia source (7).
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP22183389.0A EP4303488A1 (en) | 2022-07-06 | 2022-07-06 | Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus |
PCT/EP2022/083819 WO2023025970A2 (en) | 2022-07-06 | 2022-11-30 | Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP22183389.0A EP4303488A1 (en) | 2022-07-06 | 2022-07-06 | Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4303488A1 true EP4303488A1 (en) | 2024-01-10 |
Family
ID=82399348
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP22183389.0A Pending EP4303488A1 (en) | 2022-07-06 | 2022-07-06 | Method for combusting carbonaceous fuel in a fluidized bed reactor and fluidized bed apparatus |
Country Status (2)
Country | Link |
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EP (1) | EP4303488A1 (en) |
WO (1) | WO2023025970A2 (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4181705A (en) * | 1978-08-18 | 1980-01-01 | Chevron Research Company | Purification of fluidized-bed combustion flue gas |
DE3441141A1 (en) * | 1984-11-10 | 1986-05-22 | L. & C. Steinmüller GmbH, 5270 Gummersbach | Non-catalytic NOx reduction using ammonia in a fluidised-bed furnace |
US4648331A (en) * | 1984-03-02 | 1987-03-10 | Steag Ag | Process for the reduction of NOx in fluidized-bed furnaces |
EP0252893A2 (en) * | 1986-07-08 | 1988-01-13 | Abb Stal Ab | Method of reducing the content of nitrogen oxides in multiple bed combustion boilers |
EP0280016A2 (en) | 1987-02-27 | 1988-08-31 | L. & C. Steinmüller GmbH | Device for injecting a gaseous medium at a fluidised-bed process |
EP0495296A2 (en) | 1991-01-14 | 1992-07-22 | Foster Wheeler Energy Corporation | Fluidized bed combustion system having a recycle heat exchanger with a non-mechanical solids control system |
-
2022
- 2022-07-06 EP EP22183389.0A patent/EP4303488A1/en active Pending
- 2022-11-30 WO PCT/EP2022/083819 patent/WO2023025970A2/en unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4181705A (en) * | 1978-08-18 | 1980-01-01 | Chevron Research Company | Purification of fluidized-bed combustion flue gas |
US4648331A (en) * | 1984-03-02 | 1987-03-10 | Steag Ag | Process for the reduction of NOx in fluidized-bed furnaces |
DE3441141A1 (en) * | 1984-11-10 | 1986-05-22 | L. & C. Steinmüller GmbH, 5270 Gummersbach | Non-catalytic NOx reduction using ammonia in a fluidised-bed furnace |
EP0252893A2 (en) * | 1986-07-08 | 1988-01-13 | Abb Stal Ab | Method of reducing the content of nitrogen oxides in multiple bed combustion boilers |
EP0280016A2 (en) | 1987-02-27 | 1988-08-31 | L. & C. Steinmüller GmbH | Device for injecting a gaseous medium at a fluidised-bed process |
EP0495296A2 (en) | 1991-01-14 | 1992-07-22 | Foster Wheeler Energy Corporation | Fluidized bed combustion system having a recycle heat exchanger with a non-mechanical solids control system |
Also Published As
Publication number | Publication date |
---|---|
WO2023025970A3 (en) | 2023-03-30 |
WO2023025970A2 (en) | 2023-03-02 |
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