EP3650756A1 - Demounatble lance system - Google Patents

Abstract

The invention relates to a lance system (1) for introducing reagents by means of a nozzle (8) into reaction spaces (2) through which combustion gases (3) flow, the lance system (1) comprising: - a cladding tube (6) which is configured at least in part to be arranged within the reaction space (2); Cladding tube (6) has at its distal end an end plate (9) which limits the interior of the cladding tube (6) towards the outside, the end plate (9) having an internal opening (11) for arranging the nozzle (8) and the Level of the end plate (9) of the cladding tube (6) is arranged at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube, the longitudinal axis of the nozzle (8) of the injection lance (7) in the installed state d is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube (6) and is inclined towards the end plate (9); and the nozzle (8) of the injection lance (7) is arranged and aligned in relation to the inner opening of the end plate (9) so that the nozzle (8) can inject the reagent through the inner opening (11) of the end plate (9) The invention further relates to a reaction space (2) which is designed to be traversed by combustion gases, the reaction space (2) containing at least one lance system (1) according to the invention; and a method for injecting reagents in the form of fluids into combustion gases (3) within a reaction space (2) through which these combustion gases (3) flow, the reagents being injected into combustion gases (3) by means of at least one lance system (1) according to the invention that flow through the reaction chamber (2).

Description

The present invention relates to a collapsible lance system, a reaction chamber containing the lance system and a method for reducing the concentration of pollutants in combustion gases.

Technical field

The combustion of carbonaceous materials and fossil fuels, for example in power plants and steam generation plants, waste incineration plants, or cement plants, produces sulfur dioxide (SOx) and nitrogen oxides (NO _x ). In accordance with the legal requirements, measures for controlling the combustion process or for cleaning flue gases or combustion gases must be established so that only little NO _x is generated or NO _x and SO _x present in combustion gases are reduced in order to reduce the entry into the atmosphere.

The formation of NO _x is subject to complex reaction mechanisms, the most important sources of NO _{x being} the oxidation of the nitrogen in the combustion air (thermal NO _x ) and the oxidation of the fuel nitrogen (fuel NO _x ).

Thermal NO _x essentially arises at temperatures that are greater than about 1,200 ° C to 1,500 ° C, because only at these temperatures does the molecular oxygen in the air change noticeably into atomic oxygen (thermal oxidation) and with the nitrogen in the air connects. The formation rate of the thermal NO _x depends exponentially on the temperature and is proportional to the oxygen concentration.

The primary nitrogen compounds contained in the fuel initially break down into secondary nitrogen compounds (simple amines and cyanides), which are converted to either NO _x or N ₂ in the course of combustion. If there is a lack of oxygen, the formation of N _{2 is} preferred or the formation of NO _{x is} suppressed or even reversed. The formation of fuel NO _x is only slightly temperature-dependent and takes place even at low temperatures.

In power plants, NO _{x is reduced} in the prior art by means of primary measures such as air grading at the burner and above the combustion chamber height. The air grading above the combustion chamber height is carried out in such a way that the burner belt area is usually operated under substoichiometric. This means that the burners only receive part of the amount of air required for complete combustion. The remaining air required for burnout (= ABL = burnout air) is then generally added at a clear distance above the burner belt. This procedure is referred to as the OFA (over-fire air) process. The addition is made using so-called ABL nozzles. The two basic types of ABL nozzles are wall nozzles and ABL lances.

Application of SNCR as a secondary measure for nitrogen oxide reduction

The invention relates to a method and devices including reaction spaces for reducing undesirable substances by injecting a reactant into an exhaust gas or flue gas, in particular into the exhaust gas of cement plants, in which the reaction medium is injected into the flue gas by means of lances. Furthermore, the invention relates to a lance or a lance system for the injection of reactants to reduce undesirable substances in the flue gas. In addition, the invention also relates to a suitable reaction space which is equipped with such a device according to the invention in order to be able to carry out the process.

Methods and devices of the aforementioned type are already known. The reactants are, for example, ammonia and / or urea, which can reduce the proportion of nitrogen oxides in the flue gas. Appropriate processes are called selective non-catalytic reduction (SNCR; selective non-catalytic reduction). In the selective non-catalytic reduction (SNCR) of nitrogen oxides, reducing agents are injected into the hot flue gases of an incineration plant in aqueous solution (typically ammonia water, urea) or in gaseous form (ammonia). The reaction of the reducing agent with nitrogen oxide and oxygen produces molecular nitrogen, water and carbon dioxide. For ammonia or urea as the reducing agent, for example, the following simplified reaction takes place:

4NH ₃ + 4NO + O ₂ → 4N ₂ + 6H ₂ O

2NH ₂ CONH ₂ + 4NO + O ₂ → 4N ₂ + 2CO ₂ + 4H ₂ O

The optimum temperature range for the reactions described is between 850 and 1,000 ° C, depending on the flue gas composition.

One of the main difficulties with SNCR technology is to mix the reducing agent into the flue gas in the correct temperature window. Basically, the SNCR technology is successfully used in small and medium-sized boilers and especially in waste incineration plants and cement plants. The advantage here is the small cross-sections of the reaction or combustion chambers, so that the SNCR technology can be used effectively and in an optimized manner.

In cement plants, cement is produced in a continuous process using the dry process in rotary kilns. The raw materials such as limestone, clay, sand, but also often residues such as "fluff" or "bram", etc. are ground and at the same time dried, then warmed up and then fired into cement clinker. The cement clinker is fired in rotary kilns that are slightly inclined. As a result of the inclination and rotation of the furnace, the preheated raw meal placed at the upper end runs towards a coal dust, oil or gas flame that burns at the lower end of the furnace. In the area of the flame with gas temperatures of 1,800 to 2,000 ° C, firing material temperatures of 1,350 to 1,500 ° C are reached. The raw meal is preheated and calcined either in the rotary kiln itself or in a separate preheater, which is usually constructed from a device consisting of several cyclones, or in a separate calciner (Calcination reactor). The hot exhaust gases from the rotary kiln flow through the calciner and preheater from bottom to top, and the dry raw meal is added to the exhaust gases before the top cyclone stage, separated from the gas in the individual cyclones and suspended again in the gas stream before the next cyclone stage. The raw meal is usually preheated to a temperature of approx. 800 ° C in the preheater. A partial calcination of the raw meal can already take place in the cyclone preheater. The raw meal is then further calcined in the calciner before it reaches the rotary kiln.

At the high temperatures of the burning flame, nitrogen oxides are formed in a large amount in the rotary kiln, which must be removed from the exhaust gases.

SNCR systems for power plants, waste incineration plants and cement plants have already been described in the prior art. As a rule, only very short injection lances are used, the nozzles either essentially being flush with the reactor or channel wall or not projecting more than a few decimeters into the hot space. The reason for this is that a temperature of 850 to 1,000 ° C is required for the functioning of an SNCR and a long lance of this temperature protruding into the room and especially when used in cement plants extremely high dust loads in the flue gas and thus also a strong formation of deposits or erosion.

The central areas of the flue gas flows in flue gas ducts and combustion chambers with large cross-sectional dimensions can only be reached, if at all, by using the reagents in large quantities in the wall. With increasingly strict limits for NO _x (e.g. <200 or even 150 mg / Nm ³ dry, depending on the application based on different oxygen concentrations (e.g. based on 10% O ₂ in cement plants and based on 6% O ₂ in coal-fired power plants), must also the center of the duct or combustion chamber can be better reached with reagent, which uses disproportionate amounts of ammonia or urea solution for the SNCR, which also remain in not inconsiderable amounts without finding a reaction partner unreacted as so-called ammonia slip in the flue gas. Some of this ammonia slip burns as a result, some of it leaves the gas space through the chimney. In addition, there is also the risk that larger amounts of unreacted ammonia get into the filter ash, which is undesirable due to the smell and the toxicity. In any case, the input costs rise significantly due to the non-earmarked contribution of the input material not involved in the reaction.

This is how the German patent application describes it DE 43 13 479 a process for the denitrification of the waste gases resulting from the production of cement, the ammonia being added to the waste gas after leaving the rotary kiln at a temperature of 750 to 950 ° C., and the waste gas at a temperature of 300 to 450 ° C. with catalytically active substances is brought into contact. The injection nozzle for the ammonia is not described in more detail in the document.

The WO 93/19837 discloses a process for the denitrification of the exhaust gases which are produced in the production of cement. After leaving the rotary kiln, an ammonia solution is added to the exhaust gas via wall-mounted nozzles.

The WO 2014/114320 describes a process for the treatment of nitrogen-containing exhaust gases from technical processes, such as flue gases, for reducing the nitrogen oxide content by means of chemical reduction of the nitrogen oxides. The reducing agent is injected into the reaction space through which the exhaust gases flow via nozzles arranged in the wall of the reaction space.

The EP 2 962 743 A1 discloses the introduction of reducing agent into a boiler. The reducing agent is injected using lances into which one or more injectors for reducing agents are introduced. Burnout air is also supplied to the lances, for example. The reducing agent is injected into the lance and leaves the lance together with the burnout air through the nearest outlet openings of the lance into the flue gas.

The US 5,342,592 discloses an injection lance with an outer tubular jacket with a plurality of openings and a cooling circuit. This tubular casing has an inner channel into which an injection lance is inserted. This in turn consists of an inner tube and an outer tube, with an intermediate space being formed. The reducing agent is passed through the inner tube and the blowing agent through the gap. The reducing agent passes directly into the flue gas stream from the inner pipe and via radial ducts bridging the intermediate space. The blowing agent meets the reducing agent at the outlet of these channels and enters the flue gas stream.

The US 5,281,403 describes an injection lance system with an inner tube and an outer tube, which form an intermediate space through which the reducing agent is fed into a boiler. The reducing agent is introduced into the inner tube, which is provided with a plurality of nozzles along the longitudinal orientation of the inner tube. A carrier gas is introduced into the cavity of the outer tube. The nozzles of the inner tube inject the reactant into the flue gas through a respectively arranged outlet opening in the outer tube, the reagent being simultaneously mixed with the carrier gas, which is passed into the cavity of the outer tube and likewise leaves the lance system through said outlet opening.

As explained above, various devices for the injection of reagents for reducing the NOx concentration in calciners of cement plants were already known in the prior art. In addition to the wall nozzles described, lances were also used for this purpose, such as, for example, two-substance nozzles spraying downwards, through which an ammonia / air mixture is atomized in the smoke gas flow direction. The nozzle of such a conventional lance is surrounded by an annular gap, through which, by means of a high overpressure, an envelope or veil of air is generated around the nozzle, which is intended to protect the nozzles against caking by the raw cement powder flying past in the calciner.

However, these prior art nozzles proved to be of little use in real operation of a cement plant, which is why the area around the nozzles and even the nozzles themselves were covered by thick crusts and caking from raw meal after only a short operating time of only a few hours. The reason for this rapid growth of stable incrustations is, on the one hand, due to the extraordinarily high dust content in the calciner gas volume flow of approx. 900 g / Nm ³ and, on the other hand, the fact that this dust (ie the raw cement meal) must naturally have the property stick together well and on walls. With the conventional nozzles or lance systems, a uniform spray pattern in all spatial directions can no longer be maintained after a few hours of operation. Furthermore, cleaning the nozzles as often as would be necessary for the operation of a cement plant is out of the question. It was therefore desirable to provide injection lances and systems that need to be cleaned at most once a week or less.

Another problem of the injection lances according to the prior art was that thick and well-adhering caking of raw meal occurs on the section of the injection lance arranged within the reactor space or the calciner after a short period of operation, so that the complete lances are only extremely can be pulled out completely and with great effort. Maintenance and repair work on such conventional lances is therefore very tedious and time-consuming and costly.

Object of the invention

It was therefore an object of the present invention to provide lance systems, in particular for injecting reagents for flue gas purification, such as with regard to NO _x , and in particular in reaction rooms such as calciners, flue gas ducts, boilers or combustion chambers, which flow through hot flue gases with a high dust load and which Lance systems are flowed around by these hot flue gases, the lance systems allowing longer maintenance intervals and in particular maintenance and repair work can be carried out faster and with less effort.

• ein Hüllrohr, das konfiguriert ist mindestens zum Teil innerhalb des Reaktionsraumes angeordnet zu werden;
• eine Eindüslanze mit einem Zuführrohr für ein Flüssigreagenz, ggf. einem Zuführrohr für Druckluft, und mit der Düse zum Eindüsen des Reagenz, wobei die Eindüslanze in das Hüllrohr eingeschoben werden kann;

wobei erfindungsgemäß
das Hüllrohr an seinem distalen Ende eine Abschlussplatte aufweist, die den Innenraum des Hüllrohrs nach außen hin begrenzt, wobei die Abschlussplatte eine innenliegende Öffnung zur Anordnung der Düse aufweist und die Ebene der Abschlussplatte des Hüllrohrs in einem Winkel von 25 bis 65° zur Längsachse des Hüllrohrs angeordnet ist,
die Längsachse der Düse der Eindüslanze im eingebauten Zustand in einem Winkel von 25 bis 65° zur Längsachse des Hüllrohrs abgewinkelt ist und zur Abschlussplatte hin geneigt ist; und
die Düse der Eindüslanze im Verhältnis zur innenliegenden Öffnung der Abschlussplatte so angeordnet und ausgerichtet ist, so dass die Düse das Reagenz durch die innenliegende Öffnung der Abschlussplatte hindurch eindüsen kann.The technical problem is solved by a lance system for introducing reagents by means of a nozzle into reaction spaces through which combustion gases flow, the lance system comprising:

• a cladding tube configured to be at least partially disposed within the reaction space;
• a injection lance with a feed tube for a liquid reagent, possibly a feed tube for compressed air, and with the nozzle for injecting the reagent, the injection lance being able to be inserted into the cladding tube;

being according to the invention
the cladding tube has at its distal end an end plate which limits the interior of the cladding tube to the outside, the end plate having an internal opening for arranging the nozzle and the plane of the end plate of the cladding tube at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube is arranged
the longitudinal axis of the nozzle of the injection lance in the installed state is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube and is inclined towards the end plate; and
the nozzle of the injection lance is arranged and aligned in relation to the inner opening of the end plate so that the nozzle can inject the reagent through the inner opening of the end plate.

As mentioned above, reagents, in particular in the form of fluids, ie in particular in the form of gases and / or liquids, are injected into combustion gases in order to reduce the pollution. The reaction spaces through which combustion gases flow are preferably calcinators or calcining reactors, flue gas ducts, boilers or combustion chambers. According to the invention, the angle of incidence is now the nozzle, which is located at the distal end or at the lance head, ie at the inside through which combustion gases flow of the reaction chamber protruding end of the lance system, beveled. The "distal end" of the lance system is the end which projects into the interior of the reaction space.

According to the invention, the angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube is in a range from 25 to 65 °. The definition that the longitudinal axis of the nozzle of the injection lance in the installed state is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube and is inclined towards the end plate means that the longitudinal axis of the nozzle is at an angle of 90 ° +/- 10 ° to the level of the end plate. The angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube is preferably in the range from 30 to 60 °, more preferably in the range from 35 to 55 °, and particularly preferably around 45 °.

The end plate can be flat or concave or convex. If the end plate is curved, the level of the end plate refers to the imaginary plane that is defined by the edge of the end plate.

According to the invention, the nozzle of the injection lance is arranged and aligned in relation to the inner opening of the end plate so that the nozzle is seated in the inner opening of the end plate, a gap extending around the nozzle remaining or being able to remain. The “inner opening” of the end plate is an opening or a corresponding through hole arranged within the surface of the end plate. This opening or this through hole can be arranged substantially centered with respect to the surface of the end plate. Due to the arrangement of the end plate inclined to the longitudinal axis of the cladding tube, it has an oval shape. In a preferred embodiment, the nozzle of the injection lance at least partially passes through the inner opening of the end plate in the installed state, with a preferably all-round or uninterrupted gap remaining between the nozzle of the injection lance and the edge of the inner opening of the end plate.

The inventive adjustment of the angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube, in comparison to a right angle, in conjunction with the likewise inclined end plate, allows the injection lance to be withdrawn through the cladding tube, which remains in place in the reaction space . This also makes it possible for the nozzle or the nozzle head a piece, preferably 6 to 8 mm, can protrude beyond the end plate in the direction of the reaction space, which would not be possible with a 90 ° deflection. This has the advantage that the risk of caking due to liquid droplets spraying directly from the nozzle onto the parts of the cladding tube surrounding the nozzle is greatly reduced. Therefore, it is further preferred that the nozzle of the injection lance protrudes through the inner opening of the end plate in the installed state, preferably 2 to 10 mm and particularly preferably 4 to 8 mm through the inner opening of the end plate. In contrast, aligning the nozzle along the longitudinal axis of the cladding tube (angle 0 °) in accordance with the wall nozzles of the prior art has the disadvantage of less coverage of the cross section of the reaction space with reagent.

In a preferred embodiment, a completely circumferential or uninterrupted gap remains in the installed state between the nozzle of the injection lance and the edge of the inner opening of the end plate.

In a further preferred embodiment, the end plate of the cladding tube is dimensioned such that a completely circumferential or uninterrupted gap is provided between the edge of the end plate and the inner wall of the cladding tube.

In a very particularly preferred embodiment, a completely circumferential or uninterrupted gap remains between the nozzle of the injection lance and the edge of the inner opening of the end plate in the installed state, and a completely circumferential or uninterrupted gap between the edge of the end plate and the inner wall of the cladding tube. According to this embodiment, during operation it is achieved that the envelope air emerging from the envelope tube through the two gaps in the form of two envelope air curtains lying one inside the other surrounds the reducing agent / air mixture injected through the nozzle.

With these measures, according to the preferred embodiments of the present invention, two concentric enveloping air ring gaps are now provided around the nozzle instead of only one enveloping air ring gap as previously in the prior art. The outer The gap runs uninterruptedly around the inclined end plate and flushes the gap between the outer area of this plate and the inner area of the lance tube. If cement dust gets through this outer veil of the enveloping air despite the repellent outer envelope air curtain, the cement dust is finally prevented from reaching the nozzle itself and its liquid droplets by the inner envelope air curtain, which directly surrounds the nozzle.

In a further preferred embodiment of the lance system, the end plate of the cladding tube has further through holes or cladding air holes. These serve to keep the oblique cover plate with enveloping air, which flows from the inside of the cladding tube, free of cement dust. Preference is given to 3 to 10 enveloping air holes, preferably 4 to 6, particularly preferably 5 enveloping air holes which surround the inner opening of the end plate, i.e. in the installed state, are arranged around the nozzle or around the gap between the nozzle and the edge of the inner opening of the end plate.

• über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte des Hüllrohrs;
• über den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs;
• über ggf. weitere vorhandene Durchgangslöcher in der Abschlussplatte.

In a further embodiment, the lance system therefore has an intermediate space which is formed between the outer wall of the injection lance and the inner wall of the cladding tube, the intermediate space being in fluid communication with the outside via at least the following outlet openings:

• over the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate of the cladding tube;
• over the gap between the edge of the end plate and the inner wall of the cladding tube;
• about any further through holes in the end plate.

In a further embodiment it is preferred that the lance system is constructed in such a way that
the injection lance by means of ramp-like bevelled rails arranged on the inner wall of the cladding tube, into which guide lugs arranged on the side of the injection lance engage, inserted into the cladding tube and aligned and releasably fixed within the cladding tube, or
the injection lance can be inserted into the cladding tube and aligned and detachably fixed within the cladding tube by means of guide lugs arranged on the inner wall of the cladding tube, which engage in ramp-like slanted rails arranged on the side of the injection lance. Another preferred embodiment of the lance system is designed such that the distance between the injection lance and the cladding tube is maintained by additional spacers, these spacers preferably being selected from the group consisting of fins, pins, rods, webs or guide plates.

The supply for the reducing agent is preferably designed as a two-substance nozzle, the reducing agent being introduced together with a blowing agent (preferably compressed air). In an advantageous and preferred manner, the injection lance has a central line for introducing the reducing agent (liquid reagent feed tube), and an intermediate space between the central line and the inner wall of the injection lance, via which a blowing agent (compressed air) is conducted separately from the supply of the reducing agent is to be mixed in the nozzle with the reducing agent and atomize it. It is therefore preferred in a further embodiment that the injection lance has a liquid reagent supply pipe and a compressed air supply pipe, the liquid reagent supply pipe preferably running in the compressed air supply pipe.

For the assembly of the lance system according to the invention, the angled nozzle, which is firmly connected to the feed tube for reagent and to the feed tube for compressed air, is ideally automatically centered into its end position into the inner opening by means of lateral guide lugs or ramp-like slanted rails when inserted into the cladding tube the end plate. Correct positioning is important because the gap between the nozzle and the edge of the internal opening should be approximately the same width all around.

Optionally, the gap around the nozzle can also be provided somewhat wider in the axial direction, ie to the front and back along the direction of insertion, since here the different temperature expansion between the outer cladding tube and the injection lance requires a certain amount of leeway.

Reaction rooms, such as calcinators, flue gas ducts or boilers or combustion rooms, some of which have large cross-sections, must be exposed to the appropriate reagents over the entire cross-section in order to optimally reduce pollutants. In comparison to the injection of reagents with nozzles arranged directly in the wall of these reaction spaces, as is usually done in the prior art, a far more effective flue gas cleaning effect can be achieved with the lance system according to the invention and thus a lower pollutant clean gas value with moderate use of reagents . With the lance system according to the invention, the reagents can now also be reached in the central areas of the cross-section of reaction spaces that have not previously been able to be supplied with reagent. In the example of the SNCR, this means that due to the better accessibility also in the middle of the reaction space, a lower clean gas final value, for example of NO _x, and thus compliance with a stricter limit value (e.g. <200 or even <150 NO _x mg / Nm ³ dry, based on 6% O ₂ ) can be achieved without having to use a disproportionate amount of ammonia or urea solution, which then remains in considerable amounts afterwards, without having found a reaction partner, unreacted as so-called ammonia slip in the flue gas at the fireplace . There is also a risk that larger amounts of unreacted ammonia get into the filter ash, which is undesirable due to the toxicity and the smell.

Furthermore, the lance system according to the invention can also be used in dust-laden combustion gases, in particular in calciners of cement plants, because the invention provides measures for the quick and easy disassembly and disassembly of the lance system for subsequent maintenance and cleaning, and preferably means for protecting the nozzles against caking.

1. a) Reagenzien in Form eines fluiden Gemisches enthaltend Reduktionsmittel durch ein in der Eindüslanze verlaufendes Flüssigreagenz-Zuführrohr zuzuführen und von dort über die Düse direkt durch die innenliegende Öffnung der Abdeckplatte des Hüllrohrs hindurch nach außen zu leiten;
2. b) Hüllluft in den Zwischenraum zwischen der Eindüslanze und der inneren Wand des Hüllrohrs getrennt zuzuführen;
3. c) einen Teil der Hüllluft aus b) über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte aus dem Hüllrohr austreten zu lassen, wodurch ein innerer Hüllluftschleier gebildet wird; und
4. d) einen anderen Teil der Hüllluft aus b) durch den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs aus dem Hüllrohr austreten zu lassen, wodurch ein äußerer Hüllluftschleier gebildet wird.

It is further preferred that the lance system is constructed

1. a) feeding reagents in the form of a fluid mixture containing reducing agent through a liquid reagent feed pipe running in the injection lance and from there via the nozzle directly through the inner opening of the cover plate of the cladding tube to the outside;
2. b) supplying envelope air separately into the space between the injection lance and the inner wall of the envelope tube;
3. c) to let a part of the enveloping air from b) emerge from the cladding tube via the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate, as a result of which an inner enveloping air curtain is formed; and
4. d) to let another part of the envelope air from b) emerge from the envelope tube through the gap between the edge of the end plate and the inner wall of the envelope tube, as a result of which an external envelope air curtain is formed.

It is further preferred that this supply for the enveloping air for the intermediate space is arranged in an outer section of the lance system, which is designed to supply the enveloping air to the intermediate space between the injection lance and the enveloping tube. Thus, the cladding tube has an inner end (which projects into the reaction space) and an outer end, the outer end being in fluid communication with a supply for introducing the cladding air into the intermediate space.

The enveloping air introduced through the space between the cladding tube and the injection lance of the lance system serves to cool the lance system and to avoid deposits on the nozzle. The enveloping air is introduced into the outer tube of the lance system and forwarded into the space between the injection lance and the outer tube. The enveloping air finally exits through the gaps around the nozzle (or through the inner opening of the end plate of the cladding tube), through the gaps between the outer edge of the end plate and the cladding tube and possibly through further through holes in the end plate, ie into the interior of the reaction space. The enveloping air surrounds the reducing agent / air mixture injected through the nozzle in the form of two enveloping air curtains (the inner and the outer enveloping air curtain) and finally hits the combustion gas. In particular, the enveloping air or the enveloping air curtain also prevents caking on the nozzle or on the outlet openings, in that possibly moistened and agglomerated dust particles are kept away.

With the lance system according to the invention, reagents, such as nitrogen oxide reducing agents, can be mixed into a combustion gas as evenly as possible.

In a further preferred embodiment, the lance system is designed to introduce reducing agents for the selective non-catalytic reduction of nitrogen oxides in combustion gases into the reaction spaces through which combustion gases flow.

In a further embodiment, the lance system has an inner section that is designed to be arranged within the reaction space and an outer section that is designed to be arranged outside the reaction space, wherein a quick-action coupling is provided to the injection lance through the insert the outer section arranged opening of the cladding tube into the cladding tube and fasten by means of the quick release coupling. The quick release coupling is used to be able to quickly and easily install and remove the injection lance. With the quick release coupling, the connection between the two lance parts "cladding tube" and "injection lance" can be made quickly and also released again. So far, a flange with several screws was provided at this point, but this means much more effort for maintenance and repair work on the lance system.

Furthermore, the lance system is preferably designed to handle combustion gases with a dust load of 1 g / Nm ³ up to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, preferably from 30 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, more preferably from 100 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h. The dust load of combustion gas streams in the combustion chamber of power plants is typically in the range from 1 g / Nm ³ to 10 g / Nm ³ , while the dust load, for example in calcining reactors in cement plants, is in the range from 100 g / Nm ³ to 1000 g / Nm ³ .

In a preferred embodiment, the cladding tube has a round or circular cross section.

In a preferred embodiment of the lance system, the diameter of the cladding tube decreases in the direction of the end projecting into the reaction space, i.e. towards the inner (distal) end. This measure serves to maintain the speed of the mass flow in the intermediate space and to reduce the weight of the lance system. This measure will usually only be necessary for longer lances. The cladding tube can be tapered continuously or in stages.

In a preferred embodiment of the lance system, a protective hood is formed as an extension of the cladding tube at the end projecting into the reaction space, which partially runs around the end plate and projects beyond the end plate. The protective hood preferably extends over a distance along the circumference from 1/3 to 1/2 of the circumference of the cladding tube. The protective hood is arranged on the side from which the flow of the combustion gases or the dust particles, in particular the cement dust particles, comes. This protective hood serves to ensure that the nozzle is not directly exposed to the combustion gases or the dust particles, in particular the cement dust particles.

materials

In a further very particularly preferred embodiment, the cladding tube is made from a high-temperature, heat and scale-resistant, sintered, oxide dispersion-strengthened metallic material, i.e. from a steel or a super alloy.

In a further preferred embodiment, at least one outer, highly wear-resistant coating is applied to the cladding tube by means of cladding.

The oxide dispersion strengthened (ODS) steel or such an alloy consists of a mixture of a powder of a heat-resistant, heat-resistant alloy and a very finely ground powder of a high-melting ceramic, preferably yttrium oxide (Y ₂ O ₃ ), zirconium oxide ( ZrO ₂ ) or hafnium oxide (HfO ₂ ), particularly preferably yttrium oxide (Y ₂ O ₃ ). These oxide dispersion-strengthened materials therefore essentially consist of metallic base materials, in which highly stable or inert oxides are very finely distributed. These inert particles do not change up to the melting point of the metallic matrix and are also insoluble in the melt. The high-melting oxide prevents migration of dislocations in the metallic material and therefore contributes to the high creep resistance, especially at high temperatures, for example from gases above 1,000 ° C to 1,250 ° C.

Both components - the powder of a heat-resistant, heat-resistant alloy and the very finely ground powder made of a high-melting ceramic - are intimately mixed, pressed and sintered at high temperatures, but without melting. The result is a material with a sufficiently high strength at very high temperatures.

The highly heat-resistant, heat and scale-resistant sintered metallic material is an oxide dispersion strengthened steel or an oxide dispersion strengthened superalloy. A suitable and preferred oxide dispersion-strengthened steel contains 70.0 to 80.0% by weight of Fe, 0.0 to 10.0% by weight of Al, 10.0 to 25.0% by weight of Cr, 0, 0 to 1.0% by weight of Ti and 0.05 to 1.5% by weight of oxides of one or more elements selected from the group Y, Zr, Hf, preferably Y.

In a further preferred embodiment, the highly heat-resistant, heat and scale-resistant, sintered, oxide dispersion-strengthened superalloy contains 65.0 to 80.0% by weight of Ni, 10.0 to 20.0% by weight of Cr, 0.5 to 10.0% by weight Al, up to 0.1% by weight C, up to 0.5% by weight Ti and up to 1.5% by weight oxides of one or more elements selected from the group Y, Zr, Hf, preferably Y.

In a further preferred embodiment, the high-temperature, heat and scale-resistant, sintered, oxide dispersion-strengthened superalloy contains 55.0 to 70.0% by weight of Ni, 18.0 to 25.0% by weight of Cr, 6.0 to 12.0% by weight Mo, 3.0 to 6.0% by weight Fe, 2.5 to 4.5% by weight Nb / Cb, up to 0.1% by weight C, to 0, 5% by weight of Al, up to 0.5% by weight of Ti and up to 1.5% by weight of oxides of one or more elements selected from the group Y, Zr, Hf, preferably Y.

• PM 3000 (Nominale chemische Zusammensetzung in Gewichts-%): 67,0 Ni, 20,0 Cr, 6,0 Al, 3,5 W, 2,0 Mo, 0,15 Zr, 0,01 B, 0,05 C, 1,1 Y₂O₃;
• FeCrAlMo-Legierung (chemische Zusammensetzung in Gewichts-%): 20,5 bis 23,5 Cr, 5,0 Al, 3,0 Mo, 0,0 bis 0,7 Si, 0,0 bis 0,4 Mn, 0,0 bis 0,08 C, 0,5 bis 1,5 Y₂O₃, Rest Fe, insbesondere: 21,0 Cr, 5,0 Al, 3,0 Mo, 0,5 Y₂O₃, Rest Fe;
• Legierung (chemische Zusammensetzung in Gewichts-%): 58,0 Gew.-% Ni, 20,0 bis 23,0 Gew.-% Cr, 8,0 bis 10,0 Gew.-% Mo, 5,0 Gew.-% Fe, 3,15 bis 4,15 Gew.-% Nb/Cb, bis 0,5 Gew.-% Cu, bis 0,1 Gew.-% C, bis 0,4 Gew.-% Al, bis 0,4 Gew.-% Ti, bis 0,5 Si, bis 0,5 Mn, und 0,5 bis bis 1,5 Gew.-% Oxide eines oder mehrerer Elemente ausgewählt aus der Gruppe Y, Zr, Hf, bevorzugt Y.

The following materials with the chemical composition mentioned are particularly suitable and preferred metallic materials:

• PM 3000 (nominal chemical composition in% by weight): 67.0 Ni, 20.0 Cr, 6.0 Al, 3.5 W, 2.0 Mo, 0.15 Zr, 0.01 B, 0.05 C, 1.1 Y ₂ O ₃ ;
• FeCrAlMo alloy (chemical composition in% by weight): 20.5 to 23.5 Cr, 5.0 Al, 3.0 Mo, 0.0 to 0.7 Si, 0.0 to 0.4 Mn, 0 , 0 to 0.08 C, 0.5 to 1.5 Y ₂ O ₃ , balance Fe, in particular: 21.0 Cr, 5.0 Al, 3.0 Mo, 0.5 Y ₂ O ₃ , balance Fe ;
• Alloy (chemical composition in% by weight): 58.0% by weight Ni, 20.0 to 23.0% by weight Cr, 8.0 to 10.0% by weight Mo, 5.0% by weight -% Fe, 3.15 to 4.15% by weight Nb / Cb, up to 0.5% by weight Cu, up to 0.1% by weight C, up to 0.4% by weight Al, to 0.4% by weight of Ti, up to 0.5 Si, up to 0.5 Mn, and 0.5 to 1.5% by weight of oxides of one or more elements selected from the group Y, Zr, Hf, are preferred Y.

The lance system according to the present invention is also preferably designed to be highly erosion-resistant. This is achieved by an outer coating. In a preferred embodiment of the lance system, the outer highly wear-resistant coating which is applied to the cladding tube comprises (i) hard particles, the hard particles comprising at least one of carbides, nitrides, borides, silicides and oxides and solid solutions thereof, and (ii ) a binder that binds the hard particles together. The hard particles can comprise at least one transition metal carbide selected from carbides of titanium, chromium, zirconium, hafnium, tantalum, molybdenum, niobium and tungsten or solid solutions thereof. The hard particles can be present as individual or mixed carbides and / or as sintered cemented carbides.

In a further preferred embodiment of the lance system, the outer, highly wear-resistant coating which is applied to the cladding tube has hard particles containing one or more transition metal carbides or solid solutions thereof and a binder selected from the group consisting of cobalt, nickel, iron, and one heat-resistant alloy of iron, chrome and nickel with a proportion of cobalt. The hard particles preferably contain carbides of titanium, chromium, zirconium, hafnium, tantalum, molybdenum, niobium and tungsten or solid solutions thereof, the binder being selected from the group consisting of cobalt, nickel, iron, preferably cobalt, and a heat-resistant alloy Iron, chrome and nickel with a share of cobalt.

The carbides are more preferably tungsten carbide and optionally molybdenum carbide or solid solutions thereof, and the binder is cobalt or a heat-resistant alloy of iron, chromium and nickel with a proportion of cobalt. A particularly suitable and preferred highly wear-resistant coating or armor contains or consists of tungsten carbide and optionally molybdenum carbide in a binder or a matrix consisting essentially of cobalt or a heat-resistant alloy of iron, chromium and nickel with a proportion of cobalt.

In a further preferred embodiment, the coating comprises 40.0 to 50.0% by weight of tungsten carbide and 40.0 to 60.0% by weight of at least one of iron, cobalt and nickel, particularly preferably cobalt or a heat-resistant alloy made of iron , Chrome and nickel with a share of cobalt.

The outer, highly wear-resistant coating or armouring is applied by build-up welding and preferably has a thickness of at least 2.0 mm, more preferably 2.0 to 10.0 mm, and even more preferably a thickness of 2.0 to 3.5 mm on.

The highly heat-resistant, heat and scale-resistant, sintered, oxide dispersion-strengthened metallic material has very good properties for the construction of a cantilevered lance, which protrudes into rooms through which hot gases flow. The cladding tube of the lance system made of this metallic material provides This ensures the required strength properties and ensures that the cantilever lance does not bend or even tear over time, even with a length of, for example, 5 m due to its own weight and the attacking flow forces. In normal operation, this cladding tube is cooled by the constantly flowing envelope air and does not even approach the temperature of the surrounding flue gas. However, if this cooling envelope air fails, e.g. if the associated blower fails or while the injection lance is pulled out of the envelope tube for maintenance purposes or subsequently pushed back into it, the envelope tube is at an original smoke gas temperature at the point at which the lance system injects reagents, e.g. Exposed to 850 to 1,000 ° C for a period of at least a few days and is therefore not damaged.

The present invention further provides a reaction space that is designed to be traversed by combustion gases, the reaction space containing at least one lance system as described above in accordance with the invention. The inner section of the lance system is arranged inside the reaction space and the outer section of the lance system is arranged outside the reaction space. With the device according to the invention, reaction rooms such as calcinators, flue gas ducts or boilers or combustion chambers, some of which have large cross sections, can be acted upon with appropriate reagents over the entire cross section. Thus, with the device according to the invention, the reagents required for reducing pollutants can now also reach the central areas of the cross section of these reaction spaces, as well as in dust-laden and partially. combustion gases flowing at high speeds and at a temperature of about 1,000 ° C are injected.

It is particularly advantageous that reaction rooms can now be equipped with lance systems that can be quickly and easily disassembled and disassembled and reassembled and assembled, thus enabling faster and easier maintenance and cleaning of the individual parts (injection lance and cladding tube). Preferred measures also ensure protection of the nozzles against caking.

In a preferred embodiment of the reaction space, the lance system projects cantilevered into the interior of the reaction space, this cantilevered section of the lance system projecting into the interior of the reaction space preferably having a length of 15% to 50%, preferably 20% to 40% of the diameter of the interior of the reaction space. The interior of the reaction space is defined here as the inner free space of the reaction space, i.e. within any existing linings on the inner wall of the reaction space.

In a further preferred embodiment of the reaction space, the lance system projects cantilevered into the interior of the reaction space, this cantilevered section of the lance system projecting into the interior of the reaction space preferably having a length of at least 0.5 m, preferably a length of at least 1.0 m, more preferably has a length of at least 2.0 m, even more preferably has a length of at least 3.0 m, and particularly preferably has a length of at least 4.0 m. It is further preferred that a length of 5.0 m is not exceeded.

In a further preferred embodiment, the reaction chamber is a calciner of a cement plant, which is designed to allow the combustion gas, which is passed directly or indirectly from a rotary kiln, to flow through the calciner and to convey raw meal through the calciner in the opposite direction for calcination in the direction of the rotary kiln. The cement clinker is then produced in the rotary kiln.

Depending on the type of calciner or calcining reactor, the lance systems can be arranged horizontally or vertically in the boiler. The lances are preferably arranged horizontally since the calciner is generally flowed through vertically.

The reagent or the reducing agent for NOx is introduced via the injection lance and reaches the reaction chamber via the nozzles of the injection lance. Farther envelope air is also supplied via the lance system by directing it into the envelope tube, ie into the space between the injection lance and the envelope tube. The reagent or the reducing agent is injected from the nozzle through the outlet opening (inner opening) in the end plate of the cladding tube directly into the combustion gas stream, the reducing agent also being surrounded by enveloping air that is from the space between the injection lance and the cladding tube through the inner opening of the end plate and flows into the combustion gas stream through the gap between the edge of the end plate and the inside of the cladding tube.

In a preferred embodiment, the calciner or calcining reactor has at least one of its own fuel supply and at least one of its own combustion air supply.

In a preferred alternative embodiment, the reaction chamber is a boiler or a combustion chamber, in particular of power plants and plants for steam generation and waste incineration plants, which also contains at least one supply for fuel and at least one supply for combustion air. As a boiler or firebox, the boiler contains, in addition to at least one supply for fuel, at least one supply for combustion air according to the invention, at least one of the lance systems described above; wherein the inner section of the lance system is arranged inside the boiler and the outer section of the lance system is arranged outside the boiler. The inner section of the at least one lance system projects cantilevered into the interior of the vessel and preferably has a length of 15% to 50%, preferably 20% to 40%, of the diameter of the interior of the reaction space. It is further preferred that the inner section of the at least one lance system projects cantilevered into the interior of the boiler and preferably has a length of at least 0.5 m, preferably a length of at least 1.0 m, more preferably a length of at least 2.0 m , more preferably has a length of at least 3.0 m, and particularly preferably has a length of at least 4.0 m. It is further preferred that a length of 5.0 m is not exceeded.

Fuel and combustion air are brought together in the boiler or combustion chamber to carry out the combustion. The resulting flue gas or combustion gas flows through the furnace and then through the heating surfaces arranged downstream in the flue gas flow. In the area of the heating surfaces, below, in between or above, one or more lance systems according to the invention are arranged which supply the nitrogen oxide reducing agent.

The supply for the reagent or the reducing agent and the supply for introducing the air (envelope air) into the intermediate space between the injection lance and the envelope tube are advantageously arranged outside the reaction chamber (calciner, boiler, combustion chamber, flue gas duct). Furthermore, a supply for a propellant (compressed air) is preferably arranged in order to atomize the reagent or the reducing agent at the nozzle.

The arrangement of the lance system according to the invention in the reaction space depends on the prevailing temperatures of the combustion gas in which the nitrogen oxide is to be reduced. The optimal temperature for the conversion of NO _x by the selective non-catalytic process is in the range from 850 ° C to 1,000 ° C.

The alignment of the lance systems in the reaction space can be horizontal or vertical. In the preferred embodiments of the reaction space according to the invention, one or more lance systems according to the invention can be arranged. A plurality of lance systems are particularly preferably arranged uniformly distributed over the inner cross section of the reaction space, so that each area of the combustion gas stream is reached with the reagent or reducing agent. An even distribution of the reagent or reducing agent is achieved by arranging several lances. The lance systems can also be arranged one above the other in one or more horizontal planes, in particular when the lance systems are oriented horizontally.

In a particularly preferred embodiment of the reaction space, a plurality of lance systems are arranged parallel to one another.

As already explained above, the lance systems can be arranged horizontally or vertically in the reaction space. With a horizontal arrangement of the lance system, the nozzle, which is inclined to the longitudinal axis of the cladding tube as described above, is aligned in the direction of flow of the combustion gas stream.

In a further embodiment of the reaction space, a lateral envelope air supply connection is furthermore arranged in order to be able to blow the intermediate gap between the envelope tube and the wall of the reaction space by means of the envelope air, and in this way to cause the envelope tube to become stuck due to ingress of dusts if the dew point is possibly fallen below avoid.

The technical problem is further solved by a method for injecting reagents in the form of fluids into combustion gases within a reaction space through which these combustion gases flow, the reagents being injected into combustion gases which flow through the reaction space by means of at least one lance system as described above.

• über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte des Hüllrohrs;
• über den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs;
• über ggf. weitere vorhandene Durchgangslöcher in der Abschlussplatte.

In a preferred method, enveloping air is led into the intermediate space of the lance system, which is formed between the outer wall of the injection lance and the inner wall of the cladding tube, and from there is introduced into the combustion gas via at least the following outlet openings:

• over the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate of the cladding tube;
• over the gap between the edge of the end plate and the inner wall of the cladding tube;
• about any further through holes in the end plate.

1. a) Reagenzien in Form eines fluiden Gemisches enthaltend Reduktionsmittel durch ein in der Eindüslanze verlaufendes Flüssigreagenz-Zuführrohr zugeführt und von dort über die Düse direkt durch die innenliegende Öffnung der Abdeckplatte des Hüllrohrs hindurch in das Verbrennungsgas geleitet;
2. b) Hüllluft in den Zwischenraum zwischen der Eindüslanze und der inneren Wand des Hüllrohrs getrennt zugeführt;
3. c) ein Teil der Hüllluft aus b) über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte aus dem Hüllrohr austreten lassen, wodurch ein innerer Hüllluftschleier gebildet wird; und
4. d) ein anderer Teil der Hüllluft aus b) durch den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs aus dem Hüllrohr austreten lassen und in das Verbrennungsgas geleitet, wodurch ein äußerer Hüllluftschleier gebildet wird.

In a further preferred method:

1. a) reagents in the form of a fluid mixture containing reducing agent are fed through a liquid reagent feed pipe running in the injection lance and from there are passed through the nozzle directly through the inner opening of the cover plate of the cladding tube into the combustion gas;
2. b) Envelope air fed separately into the space between the injection lance and the inner wall of the cladding tube;
3. c) allow a part of the enveloping air from b) to emerge from the cladding tube via the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate, as a result of which an inner enveloping air curtain is formed; and
4. d) allow another part of the envelope air from b) to emerge from the envelope tube through the gap between the edge of the end plate and the inner wall of the envelope tube and pass it into the combustion gas, thereby forming an external envelope air curtain.

With the method according to the invention, reaction rooms such as calcinators, flue gas ducts or boilers or combustion chambers, some of which have large cross sections, can be acted upon with appropriate reagents over the entire cross section. This means that with the method according to the invention the reagents required for reducing pollutants can also reach the central areas of the cross-section of these reaction spaces and these reagents can also be stored in dust-laden and sometimes can inject combustion gases flowing at high speeds, around 1,000 ° C hot. With the lance construction according to the invention and the special alignment of the nozzle to the longitudinal axis of the cladding tube, an easier installation and removal of the injection lance is now possible, the cladding tube remaining in place in the reaction space. This greatly simplifies maintenance work and repairs.

The other preferred measures, especially in the nozzle area, reduce the likelihood of caking in the nozzle area, so that maintenance and cleaning intervals can be extended. For example, two concentric enveloping air ring gaps are preferably provided around the nozzle. The outer gap runs around the oblique end plate without interruption and flushes the gap between the outer region of this plate and the inner region of the lance tube. Another internal air curtain generated by the gap directly surrounding the nozzle prevents cement dust from reaching the nozzle itself and its liquid droplets.

Envelope air can be passed from the cladding tube into the combustion gas via further through holes of the cladding tube, preferably arranged in the end plate, and thereby the oblique end plate can be kept free of cement dust.

A method is particularly preferred, the combustion gases the lance system (s) with a dust load of 1 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, preferably 30 g / Nm ³ to 1000 g / Nm ³ to 2,000,000 m at a flow rate of 10,000 ³ / h, more preferably from 100 g / Nm ³ to 1000 g / Nm ³ at a volume flow rate from 10,000 to 2,000,000 m ³ / flow around h.

In a further preferred method, the combustion gases flow around the lance system at a temperature in the range from 850 ° C. to 1,000 ° C.

In particular, a method is preferred, wherein the injected reagent is a reducing agent for reducing the concentration of nitrogen oxides in the combustion gas.

In a further preferred method, the reducing agent is injected into the combustion gas within a calciner or calcining reactor of a cement works, which is passed directly or indirectly from a rotary kiln and flows through the calciner, raw meal being conveyed in the opposite direction by the calciner for calcination in the direction of the rotary kiln becomes. The cement clinker is then produced in the rotary kiln.

In a further preferred method, further combustion gas is produced in the calciner by burning a fuel.

1. a) Erzeugen eines Verbrennungsgases in einer Verbrennungszone wobei das Verbrennungsgas Stickoxide enthält;
2. b) Injizieren eines selektiven Reduktionsmittels in den Verbrennungsgasstrom innerhalb des Reaktionsraumes stromabwärts der Verbrennungszone gemäß a);
3. c) Reaktion des Reduktionsmittels mit den Stickoxiden unter Bildung von N₂ und H₂O.

Another preferred method for reducing the concentration of nitrogen oxides in a combustion gas includes the following steps:

1. a) generating a combustion gas in a combustion zone, the combustion gas containing nitrogen oxides;
2. b) injecting a selective reducing agent into the combustion gas stream within the reaction space downstream of the combustion zone according to a);
3. c) reaction of the reducing agent with the nitrogen oxides to form N ₂ and H ₂ O.

According to the invention, the reducing agent is introduced via one or more lance systems into the reaction chamber, preferably into a calciner or calcining reactor of a cement plant, into a boiler or combustion chamber of a power plant or a plant for generating steam, or into a flue gas duct, the reducing agent being introduced into over the injection lance of the respective lance system is supplied, then the reducing agent is led out of the injection lance via the nozzle directly through the inner opening of the end plate of the cladding tube to the outside. Compressed air for atomizing the reducing agent is preferably fed separately into the nozzle via the injection lance. In addition, air is led into the space between the injection lance and the cladding tube (enveloping air), the enveloping air emerging from the cladding tube through the opening (or through the gap directly surrounding the nozzle) and through the gap between the end plate and the cladding tube, and that surrounds injected reactant and finally meets the combustion gases in the reaction space.

A nitrogen-containing compound is used as the reducing agent for reducing nitrogen oxides, selected from the group consisting of: urea, ammonia, cyanuric acid, hydrazine, ethanolamine, biuret, triuret, ammelides, ammonium salts of organic and inorganic acids (for example ammonium acetate, ammonium sulfate, ammonium bisulfate, ammonium bisulfite, Ammonium formate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium oxalate), preferably urea or ammonia. The reducing agent is preferably supplied in aqueous solution (e.g. ammonia water or urea dissolved in water) or in gaseous form (ammonia) into the lance system, in particular into the injection lance, preferably into the liquid reagent feed tube.

In a preferred method, the reducing agent is mixed on or in the nozzle of the injection lance with separately supplied compressed air for atomization.

In a preferred embodiment of the method, the reagent or the reducing agent strikes combustion gas at a temperature in the range from 850 ° C. to 1,000 ° C. when it emerges from the cladding tube of the lance system.

The invention is described in more detail with reference to the figures.

characters

• Figure 1 shows a schematic longitudinal section through the lance system according to the invention.
• Figure 2 shows a detail of the nozzle and the end plate in longitudinal section.
• Figure 3 shows a view of the end plate.
• Figure 4 shows a longitudinal section through the end of the lance system with a partial view of the end plate.

The Figure 1 shows a schematic longitudinal section through the lance system 1 according to the invention. The lance system is used for introducing reagents into reaction spaces 2 through which combustion gases 3 flow, such as calciners of cement plants. The lance system 1 shown in the figure comprises a cladding tube 6, which contains an injection lance 7 with a nozzle 8 on the inside. The injection lance 7 has a feed tube for a liquid reagent 19 and a feed tube for compressed air 18. In the embodiment shown, the liquid reagent supply pipe 19 lies within the compressed air supply pipe 18.

The cladding tube 6 has at its distal end protruding into the reaction space 2 an end plate 9 which delimits the interior of the cladding tube 6 towards the outside. The end plate 9 has an inner opening 11, into which the nozzle 8 of the injection lance 7 is inserted such that a circumferential gap 11 remains between the nozzle 8 and the edge of the inner opening of the end plate 9.

According to the invention, the plane of the end plate 9 is inclined to the longitudinal axis of the cladding tube 6 so that the injection lance 7 with the nozzle 8 can be pulled out of the cladding tube 6 without the likewise inclined nozzle 8 getting caught in the opening 11 of the end plate 9. As a result, it is now possible to pull the injection lance 7 out of the cladding tube 6 for cleaning and maintenance, which remains in place in the reaction space 2. So both parts can be serviced and cleaned. In the figure, an embodiment is shown, wherein the longitudinal axis of the nozzle 8 is inclined at an angle of 45 ° to the longitudinal axis of the cladding tube and the plane of the end plate 9 is also inclined at an angle of 45 ° to the longitudinal axis of the cladding tube. As a result, the longitudinal axis of the nozzle 8 comes to lie at an angle of 90 ° to the plane of the end plate 9.

Furthermore, the construction according to the invention allows the nozzle 8 or the nozzle head to be a bit, e.g. 6 to 8 mm, can protrude beyond the end plate 9 in the direction of the reaction chamber 2, which would not be possible with a 90 ° deflection of the nozzle 8 to the longitudinal axis of the cladding tube 6. This offers the advantage that the risk of caking due to liquid droplets spraying directly from the nozzle onto the surrounding protective hood 22 is greatly reduced.

In the embodiment shown, a completely circumferential or uninterrupted gap 12 is also provided between the edge of the end plate 9 and the inner wall of the cladding tube 6. The end plate 9 is fastened to the cladding tube 6 with the aid of fastenings 10 fitted inside the cladding tube 6. These fastenings 10 are attached to the inside of the end plate 9 and in particular at a distance from the edge of the end plate 9 and to the inside of the cladding tube such that a completely circumferential or uninterrupted gap 12 remains between the edge of the end plate 9 and the inner wall of the cladding tube 6 , through which enveloping air can flow outside without obstruction.

The lance system 1 shown in the figure has two concentric enveloping air ring gaps around the nozzle 8. As explained above, the outer gap 12 extends uninterruptedly around the edge of the oblique end plate 9. In operation, the through this gap 12 enveloping air free the gap between the outer region of the end plate 9 and the inner region of the cladding tube 6. In addition to this outer enveloping air curtain, there is a further inner enveloping air curtain which is generated by the gap 11 which directly surrounds the nozzle 8. The two enveloping air curtains prevent cement dust from reaching the nozzle 8 itself and its liquid droplets.

The figure shows one of several further through holes 13 in the end plate 9, which serve to keep the oblique end plate 9 free of cement dust with the enveloping air flowing out of the cladding tube 6. These additional through holes 13 or enveloping air holes are around the inner opening 11 of the end plate 9, i.e. arranged around the gap between the nozzle 8 and thus also around the edge of the inner opening of the end plate 9.

The figure also shows guide lugs 14, which are attached to the injection lance 7, and ramp-like slanted rails 15, which are arranged on the inner wall of the cladding tube 6. The guide lugs 14 engage when inserting the injection lance 7 into the cladding tube 6 in the rails 15, so that the injection lance 7 is correctly aligned and releasably fixed within the cladding tube 6. The guide lugs 14 and ramp-like bevelled rails 15 are constructed and arranged such that when the injection lance 7 is inserted, the nozzle 8 comes to rest in the opening 11 of the end plate 9 in such a way that a gap 11 remains around the nozzle 8 and the axis of the Nozzle 8 is substantially perpendicular to the plane of the end plate 9.

The in the Figure 1 The embodiment of the lance system 1 shown has an inner section 4, which is arranged inside the reaction chamber 2, and an outer section 5, which is arranged outside the reaction chamber. As already explained, the injection lance 7 is inserted into the cladding tube 6 through the outer end of the cladding tube 6 arranged in the outer section 5 and fastened by means of a quick-release coupling 21. The quick release coupling 21 serves to be able to install and remove the injection lance 7 easily and quickly.

According to the in the Figure 1 Embodiment shown are the supply for envelope air 17, the envelope air in the space 16 between the injection lance in the outer section 5 7 and the cladding tube 6 conducts, the supply for compressed air 23 and the supply for the liquid reagent 24 are arranged.

Figure 2 shows a detail of the nozzle 8 and the end plate 9 in longitudinal section. The end of the cladding tube 6, which protrudes into the reaction space, has an end plate 9, as explained above. This limits the interior 16 of the cladding tube 6 to the outside. An inner opening 11 is arranged in the central region of the end plate 9. The nozzle 8 of the injection lance 7 is introduced into this opening 11 such that a complete circumferential gap 11 remains between the nozzle 8 and the edge of the inner opening of the end plate 9. Envelope air from this interior 11 of the cladding tube enters the reaction space through this gap 11. In this way, an enveloping air curtain is generated which (completely) surrounds the nozzle 8 and the fluid injected by this nozzle.

The detailed view shows that the plane of the end plate 9 is inclined to the longitudinal axis of the cladding tube 6. In addition, the longitudinal axis of the nozzle 8 is inclined at an angle of 45 ° to the longitudinal axis of the cladding tube 6 in the direction of the end plate 9. The design allows the injection lance 7 with the nozzle 8 to be pulled out of the cladding tube 6 without the nozzle 8 getting caught in the opening 11 of the end plate 9. In this way, the injection lance 7 can be pulled out of the cladding tube for cleaning and maintenance of the same as well as the cladding tube 6, the cladding tube 6 remaining in place protruding into the reaction space.

The view further shows the possibility that the nozzle 8 or the nozzle head can protrude somewhat beyond the end plate 9 in the direction of the reaction space 2. This would not be possible with a lance with a 90 ° deflection of the nozzle head 8 in relation to the longitudinal direction of the cladding tube 6.

The figure also shows the gap 12, which is provided all the way around the end plate 9 between the edge of the end plate 9 and the inner wall of the cladding tube 6. As already explained above, the end plate 9 is fastened to the inside of the cladding tube 6 by means of fastenings 10. The fastenings 10 are spaced on the inside of the end plate 9 from the edge of the end plate 9 as well as attached to the inside of the cladding tube, so that a completely circumferential or uninterrupted gap 12 remains between the edge of the end plate 9 and the inner wall of the cladding tube 6, through which envelope air can flow to the outside without obstruction.

The figure also shows one of several further through holes 13 in the end plate 9. These through holes 13 serve to keep the oblique end plate 9 and the nozzle 8 and surrounding areas free of cement dust with the help of the enveloping air flowing out of the cladding tube 6. These additional through holes 13 or enveloping air holes are around the inner opening 11 of the end plate 9, i.e. arranged around the gap between the nozzle 8 and thus also around the edge of the inner opening of the end plate 9.

The Figures 3 and 4 show a view of the end plate 9. Figure 4 shows the same view as a longitudinal section. As explained above, the end of the cladding tube 6 projecting into the reaction space has an end plate 9 which delimits the interior 16 of the cladding tube 6 towards the outside. An inner opening 11 is arranged in the central region of the end plate 9. The nozzle 8 of the injection lance 7 is introduced into this opening 11 in such a way that a complete circumferential gap 11 remains between the nozzle and the edge of the inner opening of the end plate 9.

In addition, a gap 12 is arranged which completely runs around the end plate 9 between the edge of the end plate 9 and the inner wall of the cladding tube 6. In the embodiment shown, five through holes 13 are further provided in the end plate 9, which are arranged around the inner opening 11 of the end plate 9 and thus around the nozzle 8. At the end of the lance system, a protective hood 22 is formed as an extension of the cladding tube 6, which is arranged on the side from which the flow of the combustion gases or the flow of the cement dust particles comes. This protective hood 22 serves to ensure that the nozzle 8 and surrounding areas are not directly exposed to the combustion gases or the cement dust particles.

In addition, in Figure 3 the course of the injection lance 7 and the arrangement of the guide lug 14 and the rail 15 are indicated.

In the Figure 4 the guide within the cladding tube 6 is also shown in longitudinal section in order to correctly position the end of the injection lance 7 and in particular the nozzle 8 so that the nozzle 8 comes to rest in the inner opening 11 of the end plate 9 and a gap 11 around the nozzle 8 remains around.

In the figure, one of the guide lugs 14 arranged on the injection lance 7 can be seen which, when the injection lance 7 is inserted into the cladding tube 6 into the rail 15 (see also Figures 1 and 3rd ) intervenes. In addition, further ramp-bevelled rails 15 are shown in the figure at the end of the cladding tube 6, which serve for the exact positioning of the nozzle 8. For this purpose, corresponding guide lugs 14 or spacers 14 are also arranged in the region of the nozzle 8, which are in contact with the ramp-like slanted rails in the installed state. The rails 15, guide lugs 14 and spacers 14 are constructed and arranged such that when the injection lance 7 is pushed in, the nozzle 8 comes to lie in the opening 11 of the end plate 9 such that a gap 11 remains around the nozzle 8 and the axis the nozzle 8 is substantially perpendicular to the plane of the end plate 9.

Reference symbol list

1

Lance system

2nd

Reaction room (calciner, boiler / combustion chamber, flue gas duct)

3rd

Combustion gas

4th

inner section of the lance system

5

outer section of the lance system

6

Cladding tube

7

Injection lance

8th

jet

9

End plate

10th

Attachment for the end plate

11

internal opening in the end plate / circumferential gap around the nozzle

12

Gap between the edge of the end plate and the inner wall of the cladding tube

13

Through hole

14

Leader

15

rail

16

Space between cladding tube and injection lance

17th

Envelope air supply

18th

Supply pipe for compressed air

19th

Feed tube for liquid reagent (reducing agent or absorbent)

20th

Wall of the reaction room

21

Quick release coupling

22

Protective cover

23

Compressed air supply

24th

Liquid reagent supply (reducing agent or absorbent)

Claims (15)

A lance system (1) for introducing reagents by means of a nozzle (8) into reaction spaces (2) through which combustion gases (3) flow, the lance system (1) comprising: - a cladding tube (6) which is configured to be arranged at least in part within the reaction space (2); a injection lance with a feed tube for a liquid reagent, possibly a feed tube for compressed air, and with the nozzle for injection of the reagent, the injection lance being able to be inserted into the cladding tube; characterized in that
the cladding tube (6) has at its distal end an end plate (9) which limits the interior of the cladding tube (6) towards the outside, the end plate (9) having an internal opening (11) for arranging the nozzle (8) and the plane of the end plate (9) of the cladding tube (6) is arranged at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube,
the longitudinal axis of the nozzle (8) of the injection lance (7) in the installed state is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube (6) and is inclined towards the end plate (9); and
the nozzle (8) of the injection lance (7) is arranged and aligned in relation to the inner opening of the end plate (9) so that the nozzle (8) can inject the reagent through the inner opening (11) of the end plate (9) . The lance system (1) according to claim 1, characterized in that in the installed state the nozzle (8) of the injection lance (7) projects at least partially through the inner opening (11) of the end plate (9). The lance system (1) according to claim 1 or 2, characterized in that in the installed state a completely circumferential or uninterrupted gap (11) between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the end plate (9) remains. The lance system (1) according to any one of claims 1 to 3, characterized in that the end plate (9) of the cladding tube (6) is dimensioned such that a completely circumferential or uninterrupted gap (12) between the edge of the end plate (9) and the inner wall of the cladding tube (6) is provided. The lance system (1) according to any one of claims 1 to 4, characterized in that the end plate (9) of the cladding tube (6) has further through holes (13). The lance system (1) according to any one of claims 1 to 5, characterized in that the lance system (1) has an intermediate space (16) which is formed between the outer wall of the injection lance (7) and the inner wall of the cladding tube (6) , the space (16) being in fluid communication with the outside via at least the following outlet openings: - Via the gap (11) between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the end plate (9) of the cladding tube (6); - Via the gap (12) between the edge of the end plate (6) and the inner wall of the cladding tube (6); - Via any further through holes (13) in the end plate. The lance system (1) according to any one of claims 1 to 6, which is constructed so that the injection lance (7) by means of ramp-like slanted rails (15) arranged on the inner wall of the cladding tube (6), into which the side of the injection lance ( 7) arranged guide lugs (14) engage, inserted into the cladding tube (6) and aligned within the cladding tube (6) and can be detachably fixed, or
the injection lance (7) is inserted into the envelope tube (6) and inside the envelope tube by means of guide lugs (14) arranged on the inner wall of the envelope tube (6) and engaging in ramp-like slanted rails (15) arranged laterally on the injection lance (7) can be aligned and detachably fixed. The lance system (1) according to any one of claims 1 to 7, characterized in that the injection lance (7) is a liquid reagent supply tube (19) and a Compressed air supply pipe (18), wherein preferably the liquid reagent supply pipe (19) runs in the compressed air supply pipe (18). The lance system (1) according to any one of claims 1 to 8, characterized in that the lance system (1) is constructed a) Reagents in the form of a fluid mixture containing reducing agent through a liquid reagent feed pipe (19) running in the injection lance (7) and from there via the nozzle (8) directly through the inner opening (11) of the cover plate (9) of the cladding tube (6) to pass through to the outside; b) supplying envelope air separately into the intermediate space (16) between the injection lance (7) and the inner wall of the envelope tube (6); c) to let a part of the enveloping air from b) emerge from the cladding tube (6) via the gap (11) between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the end plate (9), thereby causing an inner Envelope air curtain is formed; and d) to let another part of the enveloping air from b) emerge from the enveloping tube (6) through the gap (12) between the edge of the end plate (9) and the inner wall of the enveloping tube (6), as a result of which an outer enveloping air curtain is formed. The lance system (1) according to any one of claims 1 to 9, characterized in that the lance system (1) has an inner section (4) which is designed to be arranged within the reaction space (2) and an outer section ( 5) designed to be arranged outside the reaction space (2), a quick-action coupling (21) being provided in order to direct the injection lance (7) through the opening of the cladding tube (6) arranged in the outer section (5) into the cladding tube (6 ) and insert it with the quick release coupling (21). The lance system (1) according to any one of claims 1 to 10, characterized in that the lance system (1) is constructed from combustion gases (3) with a dust load of 1 g / Nm ³ up to 1000 g / Nm ³ at a volume flow of 10,000 up to 2,000,000 m ³ / h, preferably from 30 g / Nm ³ up to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, more preferably from 100 g / Nm ³ flow around up to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h. A reaction space (2) which is designed to be traversed by combustion gases, characterized in that the reaction space (2) contains at least one lance system (1) according to any one of claims 1 to 11. The reaction space (2) according to claim 12, characterized in that the lance system (1) projects cantilevered into the interior of the reaction space (2) and this cantilevered section of the lance system (1) projecting into the interior of the reaction space (2) preferably has a length of has at least 15% to 50% of the diameter of the interior of the reaction space. A method for injecting reagents in the form of fluids into combustion gases (3) within a reaction space (2) through which these combustion gases (3) flow, characterized in that the reagents by means of at least one lance system (1) according to any one of claims 1 to 11 in Combustion gases (3) are injected, which flow through the reaction chamber (2). The method according to claim 14, characterized in that the combustion gases (3) the lance system (s) (1) with a dust load of 1 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, preferably from 30 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, more preferably from 100 g / Nm ³ to 1000 g / Nm ³ at a Flow around a volume flow of 10,000 to 2,000,000 m ³ / h.

Images