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WO2025219181A1 - Procédé et dispositif pour la dénitrification de gaz de fumée - Google Patents

Procédé et dispositif pour la dénitrification de gaz de fumée

Info

Publication number
WO2025219181A1
WO2025219181A1 PCT/EP2025/059747 EP2025059747W WO2025219181A1 WO 2025219181 A1 WO2025219181 A1 WO 2025219181A1 EP 2025059747 W EP2025059747 W EP 2025059747W WO 2025219181 A1 WO2025219181 A1 WO 2025219181A1
Authority
WO
WIPO (PCT)
Prior art keywords
reducing agent
flue gases
air
injection
secondary air
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
PCT/EP2025/059747
Other languages
German (de)
English (en)
Inventor
Bernd Jürgen von der Heide
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.)
Mehldau & Steinfath Umwelttechnik GmbH
Original Assignee
Mehldau & Steinfath Umwelttechnik GmbH
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 DE102024112355.9A external-priority patent/DE102024112355A1/de
Application filed by Mehldau & Steinfath Umwelttechnik GmbH filed Critical Mehldau & Steinfath Umwelttechnik GmbH
Publication of WO2025219181A1 publication Critical patent/WO2025219181A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/79—Injecting reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8631—Processes characterised by a specific device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/003—Arrangements of devices for treating smoke or fumes for supplying chemicals to fumes, e.g. using injection devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F23J2215/101—Nitrous oxide (N2O)

Definitions

  • the present invention relates to the technical field of exhaust gas treatment, in particular the treatment of flue gases containing nitrogen oxides.
  • the present invention relates to a process for denitrification of flue gases.
  • the present invention relates to a device for denitrification of flue gases.
  • the present invention relates to the use of a device for denitrification of flue gases.
  • nitrogen oxides Combustion reactions in the presence of air produce metastable, generally toxic, and reactive oxides of nitrogen, known as nitrogen oxides.
  • the formation of nitrogen oxides is enhanced by the combustion, thermolysis, and pyrolysis of organic and inorganic nitrogen-containing compounds, which occurs in large combustion plants such as combined heat and power plants or waste incineration plants.
  • Nitrogen oxides in particular the compounds nitrogen monoxide and nitrogen dioxide known as nitrous gases, which are also abbreviated to NOx, are not only toxic and cause irritation and damage to the respiratory system, but also promote the formation of acid rain because they react with moisture to form acids.
  • nitrogen oxides are also problematic for further environmental protection reasons, as they promote the formation of smog and harmful ground-level ozone, and as greenhouse gases they increase global warming.
  • the processes or measures for reducing the nitrogen oxide content of exhaust gases, especially flue gases, can be divided into primary and secondary measures:
  • the combustion process is controlled in such a way that the nitrogen oxide content in the resulting exhaust gases is as low as possible; the nitrogen oxides should not be formed in the first place.
  • primary measures include flue gas recirculation, in which the flue gas is fed back into the combustion zone, as well as air or fuel stages, in which combustion is controlled in such a way that various combustion zones with different oxygen concentrations are passed through.
  • the formation of nitrogen oxides in flue gases can also be reduced by adding additives or by quenching, i.e., by injecting water to lower the temperature during the combustion process.
  • Secondary measures are intended to reduce the concentration of nitrogen oxides in the exhaust gases, especially flue gases.
  • Secondary measures include, for example, separation processes in which the nitrogen oxides are chemically bound or washed out of the flue gas stream.
  • a disadvantage of separation processes is that large quantities of waste products, such as process water, which are often contaminated with other flue gas components, are retained and must be disposed of at great expense.
  • SCR selective catalytic reduction of nitrogen oxides
  • SCR processes generally achieve the best denitrification values, although the use of the catalyst makes the process significantly more expensive and less economically viable.
  • the systems used to implement the SCR process are extremely expensive not only to purchase but also to maintain, as the sensitive catalysts must be serviced or replaced at short intervals.
  • the fuel composition can often only be inadequately determined, such as waste incineration plants, there is therefore always a risk of catalyst poisoning due to flue gas contamination. This risk can only be reduced through additional, cost-intensive measures.
  • Selective non-catalytic reduction is based on the thermolysis of nitrogen compounds, in particular ammonia or urea, which then react with the nitrogen oxides in a comproportionation reaction to form elemental nitrogen.
  • Selective non-catalytic reduction is significantly more cost-effective than selective catalytic reduction: the costs for purchasing and maintaining SNCR systems are just 10 to 20% of the costs of corresponding SCR systems.
  • SNCR plants that operate with a combination of multiple reducing agents are the exception.
  • SNCR processes use equipment and systems designed and operated either with urea or ammonia or ammonia water.
  • systems equipped with suitable temperature measurement have proven effective. Individual injection lances or groups of injection lances are switched depending on the temperatures at the injection points, ensuring that the reactions always take place within the optimal temperature range.
  • combustion plants that are operated with grate firing and inhomogeneous fuel compositions are particularly problematic. which also cannot be evenly distributed on the grate, as is the case, for example, in waste incineration plants for domestic and industrial waste as well as for biomass. Due to the inhomogeneous fuels, the flue gas flows from the furnace are also very uneven in terms of
  • the state of the art therefore still lacks a universally applicable and cost-effective denitrification process for flue gases, particularly in cases where the flue gas quantity and composition and/or the flue gas temperature and thus the nitrogen oxide emissions fluctuate significantly.
  • An object of the present invention is therefore to avoid, or at least mitigate, the aforementioned disadvantages associated with the prior art.
  • a further subject matter of the present invention - according to a second aspect of the present invention - is a device according to claim 21; further advantageous embodiments of this aspect of the invention are the subject matter of the relevant subclaims.
  • Yet another object of the present invention - according to a third aspect of the present invention - is the use of a device according to the invention according to claim 26.
  • the subject of the present invention - according to a first aspect of the present invention - is thus a method for denitrification of flue gases from staged combustion processes, wherein
  • At least one nitrogen-containing reducing agent is introduced into the flue gases with the air for a subsequent combustion stage, in particular the secondary air, and
  • At least one nitrogen-containing reducing agent is introduced into the flue gases.
  • the second process step (b) is carried out in the form of an SCR process or an SNCR process, preferably an SNCR process, for denitrification of flue gases.
  • the process according to the invention for denitrification of flue gases thus combines a novel process step of introducing a nitrogen-containing reducing agent with the air for a subsequent combustion stage into the flue gases with a known SCR or SNCR process, preferably an SNCR process, for denitrification of flue gases.
  • nitrogen oxides are removed from the flue gases so efficiently that the limit value or a specified clean gas value of 90 mg/ Nm3 h NOx is often already achieved.
  • a base load of nitrogen oxides can thus be reliably removed by injecting the reducing agent into the air for further combustion stages, particularly the secondary air.
  • the subsequent SNCR or SCR process control then only needs to be adapted to the fluctuating residual nitrogen emissions.
  • the reducing agent By introducing the reducing agent into the air for subsequent combustion stages, especially the secondary air, not only is an outstanding reduction in the nitrogen oxide content of the flue gases achieved, but it is also possible to reduce the reducing agent consumption by 20% or more while simultaneously reducing ammonia slip. Surprisingly, almost no ammonia slip is generated in the first process step. Since significantly less reducing agent is required in the second process step compared to conventional processes, the ammonia slip of the overall process is also significantly reduced compared to conventional denitrification using SCR or SNCR processes.
  • the flue gas after cleaning can be adjusted to values below the prescribed limit values, in particular below a frequently desired clean gas value of 90 mg/hNm 3 NOx, and at the same time the ammonia slip - as already mentioned - can be completely or almost completely suppressed.
  • flue gases are in particular the volatile, in particular gaseous, combustion products which are obtained during oxidation of the fuel, for example substitute fuels, coal, waste or biomass, preferably waste or biomass, in the presence of air, as well as particles contained in or entrained therein.
  • staged combustion the fuel is typically exposed to a deficient amount of oxygen, known as primary air, to prevent complete combustion of the fuel and the excessive formation of nitrogen oxides.
  • This combustion stage is often referred to as the reduction zone, as only incomplete combustion occurs here.
  • combustion air is usually introduced in stages as primary, secondary, or tertiary air.
  • the lack of oxygen limits NOx formation in the primary combustion zone, as oxygen has a greater affinity for bonding with carbon.
  • the unburned carbon components, particularly C and CO are burned to CO2 in the flue gas flow. Further NOx formation is no longer possible or only possible to a very limited extent due to the now lower temperatures.
  • the present invention utilizes the sequence of combustion processes in staged combustions for the optimization of denitrification, in particular by means of the SNCR process, in that reducing agents are introduced into the flue gas to be denitrified with the aid of the air for subsequent combustion stages, in particular the secondary air, in particular through the secondary air openings, wherein the air for the subsequent combustion stages, in particular the secondary air, is used as a carrier medium for the reducing agents, in particular ammonia water and urea solution.
  • the flue gases which are generally too hot for the SNCR process to function in this range, are mixed with air for subsequent combustion stages, particularly the secondary air, as is common in staged combustion, to achieve complete combustion.
  • the flue gas is first cooled, and the reducing agents are shielded from the excessively hot flue gases by the combustion air and carried further with the flue gas, thus preventing the undesired combustion of the nitrogen components to NOx.
  • the secondary air is heated by mixing with the flue gas, but also by post-combustion reactions, such as the oxidation of CO to CO2 .
  • the reducing agents particularly ammonia water or urea solution
  • the urea decomposes, especially at temperatures of approximately 130°C, into reactive NH2 radicals and CO.
  • the reducing agent cannot yet react with NOx. Only when the temperature window effective for the SNCR process is reached does the reduction of NOx to molecular nitrogen and water vapor begin.
  • NOx emissions of 50 up to 80 mg/Nm 3 can be achieved. It is noteworthy that the NHs slip is always in the range of 5 mg/Nm 3 , which is due to the fact that in the first process step the reactions only take place when the reactive ammonia radicals have reached the optimal temperature window.
  • a special feature of the process according to the invention is that the reducing agent(s) can be introduced into the flue gas stream with the secondary air in the first process step (a) immediately following primary combustion. It has been shown that it is not necessary to homogenize the flue gas stream, since the reducing agent and the nitrogen oxides only react at optimal temperatures. Premature oxidation of the reducing agent is prevented by cooling or shielding by the air, especially secondary air.
  • the reducing agent is introduced into the flue gases in the first process step (a) with the air for the combustion stage, in which no further fuel is introduced into the flue gases, in particular into the burnout zone.
  • the reducing agent is therefore preferably introduced into the combustion zone in the first process step (a) in which the burnout takes place.
  • the reducing agent is introduced into the flue gases in the first process step (a) with the secondary air and/or tertiary air, preferably the secondary air.
  • the method according to the invention is carried out as a method for denitrification of flue gases, wherein fuels, in particular Solid fuels, preferably substitute fuels, coal, biomass and/or waste, are subjected to a thermal treatment, in particular combustion, with the supply of primary air, whereby flue gases are formed, whereby in a first process step (a) of denitrification, the flue gases are mixed downstream with secondary air, whereby at least one nitrogen-containing reducing agent is added to the secondary air and/or whereby at least one reducing agent is introduced into the flue gases with the secondary air, in particular whereby before, in particular upstream of, the introduction of the reducing agent into the flue gases, no process step for flue gas homogenisation is carried out, in particular no oxygen-free or low-oxygen mixing medium, in particular no water vapor or recirculated flue gas, is introduced into the flue gases and/or in particular whereby the mixing of the flue gases with the secondary air
  • denitrification is understood to mean a reduction in the content of nitrogen oxides, in particular NO and NO2.
  • the air for the further combustion stage in particular the secondary air
  • the air for the further combustion stage is introduced into the flue gases, in particular into the flue gas stream, in an amount of at least 5%, in particular at least 10%, preferably at least 20%, based on the total amount of air introduced for combustion.
  • the air for the further combustion stage in particular the secondary air
  • the air for the further combustion stage is introduced into the flue gases, in particular the flue gas stream, in an amount of 5 to 60%, in particular 10 to 50%, preferably 20 to 40%, based on the total amount of air introduced for combustion.
  • the total amount of air introduced for combustion corresponds to the amount of air supplied across all combustion stages.
  • the air for the further combustion stage in particular the secondary air and/or the Tertiary air is injected into the flue gases.
  • the air for the further combustion stage in particular the secondary and/or tertiary air, is introduced into the flue gases at a high volume flow, since this achieves effective cooling of the flue gases and sufficient shielding of the reducing agent.
  • the air for the further combustion stage in particular the secondary air and/or the tertiary air, before introduction, in particular injection, into the flue gases, has a temperature of at most 300 °C, in particular at most 250 °C, preferably at most 200 °C, preferably at most 150 °C, particularly preferably at most 100 °C, very particularly preferably at most 50 °C.
  • the air of the further combustion stage in particular the secondary air and/or the tertiary air, has a temperature in the range from 10 to 300 °C, in particular 10 to 250 °C, preferably 10 to 200 °C, more preferably 10 to 150 °C, particularly preferably 10 to 100 °C, most preferably 10 to 50 °C, before being introduced, in particular injected, into the flue gases.
  • the air for the further combustion stage in particular the secondary air and/or tertiary air
  • the air for the further combustion stage in particular the secondary air and/or tertiary air
  • the first process step of the process according to the invention is carried out as an SNCR process.
  • reducing agents are usually injected into the hot flue gases in aqueous solutions, such as ammonia water or aqueous urea solutions, or in gaseous form, such as ammonia.
  • aqueous solutions such as ammonia water or aqueous urea solutions
  • gaseous form such as ammonia.
  • the reducing agents then react with the nitrogen oxides, as shown in the example of the reducing agent ammonia. and urea, as illustrated by the following reaction equations (1) and (2), to molecular nitrogen, water and carbon dioxide.
  • the optimal temperature range for achieving a significant reduction in nitrogen oxides is typically between 850 and 1,100 °C, depending on the flue gas composition. Above this temperature range, ammonia is increasingly oxidized, i.e., additional nitrogen oxides are formed.
  • ammonia slip At temperatures below this, the reaction rate decreases, resulting in a so-called ammonia slip, which can lead to the formation of ammonia salts or ammonium salts further down the flue gas path and thus to secondary problems.
  • the ammonia slip should therefore be kept as low as possible.
  • the goal of all NOx capture processes is to achieve a high NOx capture efficiency with the lowest possible reducing agent consumption and low NH3 slip.
  • all ammonia-releasing substances such as urea, ammonia, ammonia water, etc., can be used for NOx capture in flue gases from combustion plants.
  • the reducing agents For optimal NOx capture with minimal NH3 slip, the reducing agents must be thoroughly mixed with the flue gases within the optimal temperature range. To achieve this, the reducing agents must be evenly distributed throughout the flue gas.
  • an ammonia- and/or urea-based SNCR process is used for the first process step.
  • ammonia-based SNCR processes ammonia can be used either in gaseous form or in the form of an aqueous solution.
  • urea-based SNCR processes urea is typically used in the form of aqueous solutions.
  • the urea-based SNCR process consists of the following four steps:
  • ammonia-based SNCR process operates similarly, but with one significant difference. Since ammonia does not need to be decomposed to react, the chemical reactions for NOx capture take place immediately after the ammonia water is injected into the flue gas.
  • the size of the droplets is also usually of great importance in the SNCR process:
  • Droplets that are too small would evaporate too quickly and potentially react at too high a temperature range or too close to the colder boiler walls. Both of these can negatively impact NOx capture and/or lead to increased NH3 slip. Droplets that are too large would evaporate too slowly and lead to reactions at low temperatures or even outside the temperature window, increasing NH3 slip and decreasing NOx capture.
  • Ammonia slip refers specifically to the portion of ammonia that does not react with nitrogen oxides to form elemental nitrogen.
  • the ammonia originates either from an overdose of ammonia or is a degradation product of the thermolysis of nitrogen-containing reducing agents, such as urea.
  • urea or ammonia water is used as the reducing agent, although gaseous ammonia can also be used.
  • the reducing agent For optimal nitrogen oxide removal with minimal ammonia slip, the reducing agent must be evenly mixed with the flue gases within the optimal temperature range.
  • ammonia water requires considerably more energy than urea, since ammonia has a significantly higher vapor pressure.
  • aqueous solutions of urea and ammonia have different reaction kinetics, which is mainly due to the fact that the Urea dissolved in water can only be split into reactive radicals when the water surrounding the urea particles has completely evaporated, which is why a high penetration depth into the exhaust gases is ensured with relatively low energy expenditure.
  • the ammonia evaporates from the individual water droplets immediately after entering the flue gases, so that the reaction takes place preferentially near the boiler walls.
  • the partial pressure of ammonia reaches 1 bar at 38 °C.
  • the momentum required for the optimal penetration depth of the reducing agent can only be achieved with greater energy expenditure due to its lower mass compared to a water droplet. This requires a significant increase in the corresponding steam or air volume.
  • the investment costs for a plant operated with ammonia water are significantly higher due to safety requirements, as ammonia is a toxic gas that dissolves easily in water at ambient temperature.
  • Ammonia water is therefore assigned to water hazard class 2 and is also subject to the technical guidelines for steam boilers due to its high risk potential for the environment.
  • urea solutions can be heated to temperatures up to 106 °C without evaporating ammonia gas.
  • the decomposition of urea into ammonia and carbon dioxide gas only begins at 130 °C and reaches a maximum at approximately 380 °C. Since these high temperatures cannot be reached during storage, the safety precautions required for ammonia water are not necessary.
  • urea solution is only classified as Water Hazard Class 1, meaning that it is only necessary to ensure that urea cannot enter the groundwater. A collecting tray for the storage tank is sufficient for this purpose.
  • urea solutions have the disadvantage that if urea is overdosed, it will deposit in solid form on parts of the system and lead to undesirable corrosion.
  • the urea dissolved in water can only split into reactive radicals once the water surrounding the urea particles has completely evaporated.
  • the size of the water droplets and the resulting penetration depth allow the location in the flue gas where the reactions are to take place to be determined in advance. If the water droplets are large enough and carried far enough, this allows, for example, injection into a spot too hot for NOx capture, enabling the reaction to take place at a cooler spot in the flue gas.
  • the mass of the dilution water which is used as a carrier medium for both urea solution and ammonia water, ensures a high penetration depth with relatively low energy expenditure.
  • the precise adjustment of a droplet profile or droplet size is not necessary. Instead, the reducing agent is conveyed with the air for a subsequent combustion stage, in particular the secondary air, into temperature ranges optimal for reduction. Therefore, in the first process step, the reducing agent is preferably introduced into the flue gases in the form of the finest possible droplets or as a gas.
  • the first process step of the process according to the invention thus represents a significant simplification compared to conventional SNCR processes.
  • identical or different reducing agents are used for the first process step (a) and the second process step (b).
  • different reducing agents are used.
  • Identical reducing agents mean that the reducing agents used, in particular ammonia and urea, have the same chemical structure and are used in the same concentrations.
  • Different reducing agents mean that the reducing agents differ in their chemical composition or concentrations.
  • the reducing agent is selected from the group of ammonia, urea and mixtures thereof.
  • the first process step (a) urea and/or ammonia is used as the reducing agent.
  • the reducing agent in the second process step (b) is urea and/or ammonia.
  • chemically identical compounds, in particular urea or ammonia are used as reducing agents in different concentrations for the first and second process steps.
  • the reducing agents used in the first and second process steps therefore preferably differ in their concentrations.
  • the introduction of the reducing agent into the flue gases in both process steps it has proven effective to introduce the reducing agent into the flue gases in the form of an aqueous solution or dispersion, in particular a solution.
  • the reducing agent is therefore particularly preferably introduced into the flue gases in the form of an aqueous ammonia and/or urea solution.
  • the introduction of the reducing agent into the flue gas stream in the form of aqueous dispersions or solutions, in particular solutions has the further advantage that the water evaporates upon heating, thus cooling the reducing agent and thus protecting it from premature reaction.
  • the introduction of the reducing agent into the flue gases containing nitrogen oxides, in particular the air from further combustion stages in the first process step (a), can be achieved by a variety of technical measures.
  • the reducing agent is introduced, in particular sprayed or injected, preferably injected, in the first process step (a) in a finely distributed manner into the flue gas stream, in particular the air for a further combustion stage.
  • injection can achieve a fine distribution of the reducing agent while simultaneously providing an excellent penetration depth of the reducing agent into the flue gas stream, thereby enabling a particularly effective and efficient reduction of the nitrogen oxides.
  • the reducing agent is introduced into the flue gas stream, in particular the air for a further combustion stage, by means of injection devices, in particular injection lances.
  • the nozzles of the injection device can be designed as single-fluid or dual-fluid nozzles.
  • the pressure required for injection in dual-fluid nozzles is typically generated by compressed air or steam.
  • the reducing agent in particular the aqueous solution or dispersion of the reducing agent, is introduced into the flue gases, in particular the secondary and/or tertiary air, via one or more injection devices, in particular injection lances.
  • each injection direction has one or more, in particular 1 to 20, preferably 1 to 15, preferably 1 to 10, particularly preferably 1 to 5, nozzles for introducing the reducing agent into the secondary air.
  • the injection devices can be controlled individually or in groups. It is particularly preferred within the scope of the present invention if the injection devices in process step (a) can be controlled in groups.
  • the injection of the reducing agents into the air of further combustion stages, in particular the secondary air in the first process step (a), is preferably carried out, as far as possible, into the main channels of the air supply line of further combustion stages, in particular the secondary air supply line, or into the injection openings for injecting the air of further combustion stages, in particular the secondary air nozzles.
  • the injection devices for introducing the reducing agent are assigned to individual injection openings for introducing the air for a further combustion stage, in particular for introducing the secondary air and/or tertiary air, preferably the secondary air, into the flue gases.
  • the injection devices for introducing the reducing agent into the flue gases in the first process step (a) are thus preferably arranged in the region of injection openings for introducing the air for further combustion stages, in particular the secondary air and/or tertiary air, into the flue gases, in particular the flue gas stream.
  • the air for the further combustion stage in particular the secondary air and/or tertiary air, can cool and surround the reducing agent, protecting it from premature oxidation.
  • This embodiment is particularly suitable for introducing aqueous urea solutions into the flue gas stream.
  • the injection devices for introducing the reducing agent in the first process step (a) to be assigned to collecting containers and/or main supply lines for introducing the air of a further combustion stage, in particular the secondary air and/or the tertiary air, into the flue gases.
  • the reducing agent in particular the aqueous solution of the reducing agent
  • collectors from which the injection openings for introducing, in particular injecting, the air for the further combustion stage, in particular the secondary air and/or the tertiary air, into the flue gases branch off.
  • This embodiment is particularly suitable for introducing ammonia, either in the form of aqueous solutions or in gaseous form, into the flue gas stream.
  • the temperatures of the flue gases in the first process step (a) in the region of introduction of the air for the further combustion stage, in particular the secondary air and/or the tertiary air, preferably secondary air, in particular the burnout zone, in particular at least in some regions is at least 850 °C, in particular at least 1,000 °C, preferably at least 1,100 °C, preferably at least 1,200 °C.
  • the temperature of the flue gases in the region of introduction of the air for the further combustion stage in particular the secondary air and/or tertiary air, preferably secondary air, in particular at least in some regions is 850 °C to 1,600 °C, in particular 1,000 °C to 1,500 °C, preferably 1,100 °C to 1,450 °C, preferably 1,200 °C to 1,400 °C.
  • the reducing agent in the first process step (a), the reducing agent is introduced with the air from the further combustion stage into a region of the flue gases that is fundamentally too hot, in which no reduction of nitrogen oxides is to be expected, but rather an oxidation of the introduced reducing agent.
  • the oxidation or any other reaction of the reducing agent is delayed until the reducing agent is in a temperature range optimal for the reduction of nitrogen oxides.
  • the second process stage of the process according to the invention is preferably carried out in the form of a conventional SCR or SNCR denitrification, with an SNCR procedure being preferred.
  • the introduction of the reducing agent into the nitrogen oxide-containing flue gases in the second process step (b) can be achieved by a variety of technical measures. However, it has proven to be effective within the scope of the present invention if the reducing agent is introduced into the flue gas stream in a finely distributed manner, in particular by spraying or injecting it. In particular, by injecting it, a fine distribution of the reducing agent can be achieved while simultaneously achieving an excellent penetration depth of the reducing agent into the flue gas stream, thus enabling a particularly effective and efficient reduction of the nitrogen oxides.
  • the reducing agent is introduced into the exhaust stream in the second process step (b) using injection devices, in particular injection lances.
  • the pressure required for injection is usually generated by compressed air or steam.
  • each injection device has one or more, in particular 1 to 20, preferably 1 to 15, more preferably 1 to 10, and particularly preferably 1 to 5, nozzles for introducing the reducing agent into the flue gas stream.
  • a plurality of nozzles per injection device achieves a particularly fine and uniform distribution of the reducing agent in the flue gas stream.
  • the injection devices in the second process step (b) are divided into 1 to 10, in particular 1 to 7, preferably 1 to 5, injection levels are arranged.
  • injection levels are arranged.
  • each injection level it is possible for each injection level to have 1 to 20, in particular 1 to 15, preferably 1 to 12, injection devices.
  • the reducing agent is introduced into the flue gas stream via 1 to 200, in particular 2 to 100, preferably 5 to 60, injection devices.
  • the injection devices for introducing the reducing agent are controlled individually and/or in groups, preferably individually.
  • the discharge of the reducing agent from the injection devices is controlled individually for each injection device and/or for groups of injection devices.
  • the individual injection devices are preferably controllable individually or at least in groups, since the flue gas stream is not a homogeneous entity but is subject to local and temporal fluctuations in its temperature and composition.
  • the injection devices in the second process step (b) are advantageously individually controllable, i.e., the injection devices can advantageously be individually activated or deactivated, whereby the pressure and thus the penetration depth of the reducing agent into the exhaust gas stream can also be individually controlled for each injection device. It is particularly advantageous if the individual injection devices are not only individually controlled with regard to their use and injection pressure, but if the composition of the injected reducing agent, i.e., either individual reducing agents or mixtures thereof, can be individually controlled and tailored to the respective conditions. The aforementioned individual controllability of all injection devices with regard to their operating parameters and the composition of the reducing agent leads to the best results, but also increases the process-technical effort and thus the costs of denitrification.
  • the composition or the mixing ratio of the reducing agents is set jointly for all injection devices or at least is set jointly for all injection devices of an injection level, but the individual injection devices can be individually controlled with regard to the injection pressure and the operating conditions or operating ratios.
  • a group of injection devices is understood to be a defined and/or jointly controllable and/or combined unit of a plurality of injection devices, in particular injection lances.
  • the injection device in the first method step (a) and in the second method step (b) can be controlled independently and/or separately from one another.
  • the temperatures during the introduction of the reducing agent in the second process step (b) are in the range of 50 to 1,200 °C, in particular 50 to 1,150 °C, preferably 50 to 110 °C. In these temperature ranges, denitrification is possible using both SCR and SNCR processes.
  • the temperatures of the flue gas when introducing the reducing agent in the second process step (b) are usually in the range of 50 to 500 °C, in particular 50 to 450 °C, preferably 50 to 400 °C.
  • the temperatures of the flue gas when introducing the reducing agent in the second process step (b) are in the range from 750 to 1,200 °C, in particular 800 to 1,150 °C, preferably 850 to 1,100 °C.
  • the introduction of the reducing agent into the flue gases is controlled as a function of the load signal, the flue gas temperature, the nitrogen oxide emission, the setting of the combustion output control of online calculation models and combinations thereof.
  • the introduction of the reducing agent into the flue gases is controlled as a function of the load signal, the flue gas temperature, the nitrogen oxide emission, the setting of the combustion power control of online calculation models and combinations thereof.
  • control purposes are preferably used for control purposes:
  • Boiler data such as load, steam quantity, steam parameters or flue gas quantity
  • the introduction of the reducing agent into the flue gas stream can be controlled by evaluating the load signal and/or by determining the flue gas temperature and/or by comparing a measured value for the residual nitrogen oxide content of the clean gas resulting from treatment with a predetermined target value. Furthermore, it is also possible to additionally determine the ammonia slip and also take this into account in the process control.
  • a load signal is understood to be the indication of the respective load at which a combustion device, such as a large combustion plant, in particular a boiler, is operated.
  • the load corresponds to the power released by the combustion device and is usually specified as a percentage, with full load (100%) corresponding to the power for which the combustion device is designed with optimal combustion and filling.
  • the introduction of the reducing agent into the flue gases is controlled as a function of the load signal, the flue gas temperature, the nitrogen oxide emission, the setting of the combustion power control of online calculation models and combinations thereof.
  • the second process step (b) if the temperature of the flue gases is determined during the process duration at least at defined and/or predetermined measuring points and/or if at least one temperature profile of the exhaust gases is created, in particular by means of acoustic and/or optical temperature measurement or by means of thermocouples.
  • the exhaust gas flow is divided into sections on the basis of the determined temperature values of the flue gases and/or the determined temperature profile of the flue gases, wherein defined individual injection devices and/or defined groups of Injection devices for introducing the reducing agent are assigned. This ensures that the reducing agent reaches the most effective points for a reaction, even with fluctuating flue gas temperatures, and that the plant always operates within the optimal range in terms of nitrogen oxide removal efficiency, ammonia slip, and reducing agent consumption.
  • the injection devices for introducing the reducing agent are controlled, in particular individually or in groups, on the basis of the determined temperature values of the flue gases and/or the determined temperature profile of the flue gases and/or the load signal and/or a comparison between a measured value for the residual nitrogen oxide content of the clean gas resulting after the treatment on the one hand and a predetermined target value on the other hand and/or on the basis of the settings of the combustion output control and/or on the basis of online models.
  • a further subject matter of the present invention - according to a second aspect of the present invention - is a device for denitrification of flue gases from staged combustion processes, wherein the device has at least one first injection device for introducing at least one reducing agent into a flue gas stream with the air for a subsequent combustion stage, in particular the secondary air, and wherein the device has at least one second injection device for introducing at least one reducing agent into a flue gas stream downstream of the first injection device for introducing at least one reducing agent into a flue gas stream.
  • Combustion processes primarily involve combustion processes in technical, especially large-scale, facilities such as power plants and waste incineration plants. These processes primarily involve the combustion of solid materials.
  • the device has one or more, preferably several, first injection devices for introducing at least one reducing agent into a flue gas stream.
  • first injection devices for introducing at least one reducing agent into a flue gas stream.
  • the device has 2 to 20, in particular 4 to 40, preferably 4 to 6, first injection devices for introducing at least one reducing agent into the flue gas stream.
  • the outlet of the reducing agent from the first injection devices can be regulated individually for each injection device and/or for groups of injection devices.
  • each first injection device for introducing the reducing agent into the flue gas stream has one or more, in particular 1 to 20, preferably 1 to 15, preferably 1 to 10, particularly preferably 1 to 5, nozzles.
  • the device has 1 to 20, in particular 2 to 10, preferably 4 to 8, first injection devices for introducing the reducing agent into the flue gas stream.
  • the first injection devices for introducing reducing agent into the flue gas stream are arranged in 1 or 2, preferably 1, injection levels.
  • each injection level has 1 to 10, in particular 1 to 5, preferably 2 to 4, first injection devices for introducing the reducing agent into the flue gas stream.
  • the first injection devices are designed for introducing, preferably injecting, aqueous solutions of the reducing agent, in particular aqueous ammonia and/or urea solutions.
  • the first injection device of a combustion device in particular a device for carrying out a first combustion stage of a staged combustion, preferably a combustion chamber, the primary combustion process, ie the one taking place with the supply of primary air downstream of the combustion process, in particular immediately downstream.
  • the device has one or more second devices for introducing, in particular injecting, at least one reducing agent into the flue gas stream.
  • every second injection device for introducing the reducing agent into the flue gas stream has one or more, in particular 1 to 20, preferably 1 to 15, more preferably 1 to 10, particularly preferably 1 to 5, nozzles.
  • the device has 1 to 200, in particular 2 to 100, preferably 5 to 60, second injection devices for introducing the reducing agent into the flue gas stream.
  • the second injection devices for introducing reducing agent into the flue gas stream are arranged in 1 to 10, in particular 1 to 7, preferably 1 to 5, injection levels.
  • each injection level has 1 to 20, in particular 1 to 15, preferably 1 to 12, second injection devices for introducing the reducing agent into the flue gas stream.
  • the second injection devices are designed for introducing, in particular spraying, preferably injecting, aqueous solutions of the reducing agent, in particular aqueous ammonia and/or urea solutions.
  • the second injection device is arranged between a combustion device, in particular adjacent to all devices for staged combustion, a combustion chamber and an afterburner chamber, and a heat exchange device. In this way, the best separation rates for the removal or separation of nitrogen oxides can be achieved while simultaneously low consumption of reducing agent and low ammonia slip.
  • the second injection device is connected downstream of a combustion device, in particular all devices for staged combustion, preferably a combustion chamber and a post-combustion chamber, and extends into the area of a heat exchange device.
  • a combustion device in particular all devices for staged combustion, preferably a combustion chamber and a post-combustion chamber, and extends into the area of a heat exchange device.
  • the temperature distribution and the structural conditions may result in the device according to the invention, in particular the injection lances, being located in the area of the heat exchange devices or the heating surfaces of the system or the large-scale combustion plant.
  • the device has at least one storage device, in particular a storage vessel, for storing and/or dispensing at least one reducing agent, preferably connected via at least one supply line to the first injection device and/or the second injection device, preferably the first and the second injection device.
  • a storage vessel for storing and/or dispensing at least one reducing agent, preferably connected via at least one supply line to the first injection device and/or the second injection device, preferably the first and the second injection device.
  • the device comprises: at least one first storage device, in particular a first storage vessel, preferably connected via at least one supply line to the first injection device and/or the second injection device, preferably the first and second injection devices, for storing and/or dispensing at least one first reducing agent and at least one second storage device, in particular a second storage vessel, preferably connected via at least one supply line to the first injection device and/or the second injection device, preferably the first and second injection devices, for storing and/or dispensing at least one second reducing agent different from the first reducing agent.
  • the device according to the invention is part of a system for thermal treatment, in particular for the combustion, of fuels, in particular solid fuels, such as substitute fuels, coal, biomass, or waste.
  • the plant for the thermal treatment, in particular combustion, of fuels preferably has a combustion chamber in which at least one fuel, in particular a solid fuel, preferably a solid waste, is thermally treated, in particular combusted, with the supply of primary air, producing flue gases.
  • the system preferably further comprises a post-combustion chamber or post-combustion chamber arranged downstream of the combustion chamber, in which the flue gases produced in the combustion chamber are post-combusted by supplying additional air and/or additional fuels.
  • the system comprises a post-combustion stage in which no additional fuel, but only air, is added to the flue gases, the so-called burnout zone.
  • the air for further combustion stages is introduced into the post-combustion chamber, in particular into the burnout zone, via injection openings.
  • the air from the further stages is guided via main supply lines and/or collecting containers, in particular collectors, to air injection openings for further combustion stages.
  • the first injection device for introducing the reducing agent into the flue gas flow is assigned to individual injection openings for introducing the air of further combustion stages into the post-combustion chamber and/or that the first injection device for introducing the reducing agent into the flue gases, in particular into the air for further combustion stages, is assigned to main supply lines and/or a collecting container, in particular a collector, for supplying the air for further combustion stages to the injection openings for introducing the air for further combustion stages.
  • the device has at least one water storage device for storing and/or dispensing water.
  • the water storage device preferably via at least one supply line is connected to the first injection devices and/or the second injection devices, preferably the first and second injection devices, for introducing the reducing agent.
  • the water is required in particular within the scope of the process according to the invention to precisely adjust the specific concentration ratios of the reducing agent before injection or introduction into the flue gases.
  • the device has at least one gas storage device for storing and/or dispensing optionally compressed gases, in particular compressed air and/or steam.
  • the gas storage device is connected via at least one supply line to the first injection devices and/or the second injection devices, preferably the first and second injection devices, for introducing the reducing agent into the flue gas stream.
  • the pressurization of the first injection devices for discharging the reducing agent into the flue gas stream can be carried out by means of the gases stored in the gas storage device and/or that the pressurization of the first injection devices and/or second injection devices, preferably the first and second injection devices, for discharging the reducing agent into the flue gas stream can be carried out by means of the gases stored in the gas storage device.
  • the device has at least one dosing and/or mixing device.
  • the dosing and/or mixing device is connected to the storage devices for providing the reducing agent and to the first injection devices and/or second injection devices, preferably the first and second injection devices, for providing the reducing agent and to the first injection devices and/or second injection devices, preferably the first and second injection devices, for introducing the reducing agent into the flue gas stream and is connected to any water storage facility that may be present.
  • the dosing and mixing device is designed such that the concentrations of the aqueous solutions of the reducing agent can be regulated identically and/or individually for individual injection devices, in particular for each injection device for introducing the reducing agent into the flue gas stream and/or for groups of injection devices for introducing the reducing agent into the flue gas stream, preferably for each injection device for introducing the reducing agent into the flue gas stream.
  • the first injection device and the second injection device can be regulated independently of one another.
  • the device has at least one control unit for controlling the introduction of the reducing agent through the first injection device and the second injection device.
  • the introduction of the reducing agent into the flue gas stream is controllable by determining temperature values of the exhaust gases and/or by determining a temperature profile of the exhaust gases and/or by a load signal and/or by a comparison between a measured value for the residual nitrogen oxide content of the clean gas resulting after the treatment on the one hand and a predetermined target value on the other hand and/or by setting the combustion output control and/or by online calculation.
  • the device has at least one measuring device for determining temperature values of the flue gases and/or for determining a load signal and/or for determining a value for the residual nitrogen oxide content of the clean gas resulting after the treatment, in particular for the purposes of regulating the introduction of the reducing agent into the flue gas stream.
  • the device for determining the temperature can in particular be one or more thermocouples, an acoustic temperature measuring system or an optical temperature measuring system.
  • a further object of the present invention - according to a third aspect of the present invention - is the use of a previously described device for denitrification of flue gases containing nitrogen oxides.
  • Fig. 1 shows a schematic representation of a plant 1, in particular an incineration plant, which has the device according to the invention.
  • the plant 1 has a combustion chamber 2, which is depicted in the form of a grate furnace.
  • a fuel 4 is fed into the combustion chamber 2, moved in stages over the grate 3, and removed from the plant 1 after combustion as waste or combustion residue 7.
  • the supplied fuel 4 is incompletely combusted with the aid of primary air 5.
  • the flue gases 6 produced during the incomplete combustion in the combustion chamber 2 which usually have temperatures in the range of 1,200 to 1,600 °C, rise in the combustion chamber 2 to reach subsequent combustion stages, in particular the afterburning chamber 8.
  • air for a further combustion stage in particular secondary air 9 is blown into the flue gas stream 6 together with the reducing agent 11, in particular urea and/or ammonia, preferably an aqueous urea solution and/or aqueous ammonia solution.
  • the secondary air 9 is introduced into the post-combustion chamber 8 via a supply system 10.
  • the high volume flow of the secondary air 9 protects the reducing agent 11 from the effects of excessively high temperatures and from premature reaction. In this way, it is possible for the reducing agent 11 to come into contact with the nitrogen oxides in a temperature range optimal for the reduction of nitrogen oxides, so that, in particular, unwanted oxidation of the reducing agent 11 is avoided.
  • the introduction of the reducing agent 11 into the flue gases, in particular the secondary air 9, can be carried out in a variety of ways, in particular by means of first injection lances 13.
  • the device 1 has second injection lances 14 for introducing a reducing agent into the flue gas stream 6.
  • the second injection lances 14 are used in particular for carrying out a known or conventional SCR process or SNCR process for denitrification of flue gases, preferably for carrying out an SNCR process for suffocation of flue gases.
  • the second injection lances 14 are located downstream of the first injection lances 13 for introducing the reducing agent 11, in particular downstream of the post-combustion chamber 8.
  • the injection lances 14 can be arranged in several levels, in particular 1 to 5, preferably 2 to 4, injection levels in the system 1.
  • the device preferably further comprises a temperature measuring device 15 for determining the flue gas temperature.
  • Fig. 2 shows a section along plane A through the afterburning chamber 8 of the system 1 according to Fig. 1 in a plan view.
  • the secondary air 9 is guided into the afterburning chamber 8 via a duct and collection system, in particular a supply system 10, via injection openings 12.
  • a duct and collection system in particular a supply system 10
  • injection openings 12 In the area of the injection openings 12 for injecting the secondary air 9 into the afterburning chamber 8, there are first injection lances 13 for introducing a reducing agent 11.
  • the first injection lances 13 for introducing reducing agents 11 into the flue gas stream 6 or the secondary air 9 usually have several nozzles, in particular 1 to 10, preferably 1 to 5 nozzles.
  • the first injection lances 13 can be formed in the area of the injection opening 12 for injecting the secondary air 9 into the afterburning chamber 8. However, it is also possible for the first injection lances 13 to be introduced through the injection opening 12 for injecting secondary air 9 into the afterburning chamber
  • Fig. 3 shows an alternative, likewise preferred embodiment of the device according to the invention for introducing reducing agents 11 into a flue gas stream 6.
  • Fig. 3 again shows a section along the plane A in plan view through the system 1 according to Fig. 1, wherein the first injection lances 13 for injecting the reducing agent 11 into the secondary air 9 are arranged at a central location in the supply system 10 for transporting the secondary air 9.
  • the secondary air
  • the device comprises, in particular, storage vessels (not shown) for storing and/or dispensing one or more reducing agents 11.
  • the reducing agent 11 is preferably an aqueous urea solution and/or an aqueous ammonia solution and/or gaseous ammonia, in particular an aqueous urea solution and/or an aqueous ammonia solution.
  • the storage vessels for storing and/or dispensing one or more reducing agents are preferably connected to the first injection lances 13 and/or the second injection lances 14, preferably the first injection lances 13 and the second injection lances 14.
  • the first injection lances 13 for injecting the reducing agent 11 are preferably connected via a supply line to a storage vessel (not shown) for delivering compressed air and/or steam. Compressed air is then fed through the supply line to the respective injection lances 13 and/or 14, thereby specifically adjusting the respective outlet pressure and thus the targeted penetration depth and droplet size of the reducing agent 11.
  • a storage vessel not shown
  • Compressed air is then fed through the supply line to the respective injection lances 13 and/or 14, thereby specifically adjusting the respective outlet pressure and thus the targeted penetration depth and droplet size of the reducing agent 11.
  • the device further comprises storage vessels (not shown) for storing and/or dispensing water.
  • the storage vessels for storing and/or dispensing water are preferably connected to the first injection lances 13 and/or the second injection lances 14, preferably the first injection lances 13 and the second injection lances 14.
  • first injection lances 13 and/or the second injection lances 14, in particular the first injection lances 13 and the second injection lances 14, are preferably connected to a mixing device (also not shown), which is connected via supply lines to the storage vessels containing the reducing agent 11, in particular ammonia and/or urea, preferably urea in the form of their aqueous solutions.
  • the mixing device is preferably connected to a water storage vessel via a supply line.
  • the first injection lances 13 and/or the second injection lances 14, preferably the first injection lances 13 and the second injection lances 14, can be connected to the mixing device individually or in groups, in particular via supply lines.
  • the device further comprises a control unit for controlling the introduction of the reducing agent 11 into the flue gases 6, in particular the secondary air 9.
  • the control of the introduction of the reducing agent 11 into the flue gases 6, in particular the secondary air 9, is carried out by determining the load signal, the nitrogen oxide content of the resulting clean gas in comparison to a target value, the setting of the combustion output, the temperature of the flue gases, online calculations of the combustion and the plant or combination.
  • the plant comprises devices for determining the temperature of the flue gases, in particular by means of acoustic or optical methods or by means of thermocouples, and/or that the plant comprises devices for determining the nitrogen oxide content of the clean gas, and/or devices for determining the load signal.
  • the device preferably has a temperature measuring device 15, which is arranged immediately upstream of the second injection lances 14 for injecting the reducing agent into the flue gas stream 6.
  • the procedure is now preferably such that the flue gases 6 generated in the combustion chamber 2 rise into the post-combustion chamber 8, where, based on the nitrogen oxide emissions, the load signal, the temperatures of the flue gases, the firing output setting, or on the basis of online calculations, reducing agent 11 is injected into the secondary air 9 by means of the first injection lances 13.
  • This achieves a significant and uniform reduction in the nitrogen oxide load of the flue gases 6, while at the same time ammonia slip can be completely or at least almost completely avoided.
  • the flue gas temperatures are preferably determined, in particular in a spatially resolved manner, so that further reducing agent 11 is introduced into the flue gas stream 6 in a location-selective manner by means of individual injection lances 14 or by means of groups of injection lances 14 in order to also specifically reduce the strongly varying proportion of nitrogen oxide emissions remaining after the first process step.
  • the boiler operates at a load of approximately 108%, and the flue gases are treated for 3.5 hours each using conventional SNCR technology (standard SNCR) and by injecting urea into the secondary air stream.
  • standard SNCR conventional SNCR technology
  • secondary air injection achieves a NOx removal rate of 43% and an NH3 slip of less than 8 mg/ Nm3 , compared to a NOx removal rate of 27% and a slip rate of approximately 20 mg/Nm3 with the standard SNCR system.
  • a combination of both systems achieves a higher total NOx removal rate of 57% with a significantly lower NH3 slip.
  • Table 1 Comparison of standard SNCR with injection of reducing agent into the secondary air and a combination of both processes
  • System 9 Secondary air combustion chamber 10 Feed system combustion grate 11 Reducing agent fuel 12 Primary air injection opening 13 First injection lance flue gases 14 Second injection lance combustion residue 15 Temperature measuring device post-combustion chamber

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Abstract

L'invention concerne un procédé de dénitrification de gaz de fumée issus de processus de combustion étagée et un dispositif servant à la mise en œuvre dudit procédé.
PCT/EP2025/059747 2024-04-10 2025-04-09 Procédé et dispositif pour la dénitrification de gaz de fumée Pending WO2025219181A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
DE102024109953 2024-04-10
DE102024109953.4 2024-04-10
DE102024111377.4 2024-04-23
DE102024111377 2024-04-23
DE102024112355.9A DE102024112355A1 (de) 2024-04-10 2024-05-02 Verfahren und Vorrichtung zur Behandlung von Rauchgasen
DE102024112355.9 2024-05-02

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1077077A2 (fr) 1999-08-12 2001-02-21 ABB (Schweiz) AG Procédé de traitement thermique de matières solides
EP1901003A1 (fr) * 2006-09-13 2008-03-19 MARTIN GmbH für Umwelt- und Energietechnik Procédé d'alimentation de gaz de combustion
JP2014102020A (ja) * 2012-11-19 2014-06-05 Mitsubishi Heavy Industries Environmental & Chemical Engineering Co Ltd 焼却設備

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1077077A2 (fr) 1999-08-12 2001-02-21 ABB (Schweiz) AG Procédé de traitement thermique de matières solides
EP1901003A1 (fr) * 2006-09-13 2008-03-19 MARTIN GmbH für Umwelt- und Energietechnik Procédé d'alimentation de gaz de combustion
JP2014102020A (ja) * 2012-11-19 2014-06-05 Mitsubishi Heavy Industries Environmental & Chemical Engineering Co Ltd 焼却設備

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BERND VON DER HEIDE: "NOx Reduction for the Future with the SNCR Technology for Medium and Large Combustion Plants", POWER ENGINEERING AND ENVIRONMENT VSB - TECHNICK� UNIVERZITA OSTRAVA (CZECH REPUBLIC), 3 September 2010 (2010-09-03), pages 1 - 28, XP055268811 *

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