WO2016173785A1

WO2016173785A1 - Cleaning device, calcining system, and method for cleaning a raw gas flow

Info

Publication number: WO2016173785A1
Application number: PCT/EP2016/056582
Authority: WO
Inventors: Erhard Rieder; Martin Schröter
Original assignee: Dürr Systems Ag
Priority date: 2015-04-30
Filing date: 2016-03-24
Publication date: 2016-11-03
Also published as: DE102015208029A1

Abstract

The problem addressed by the invention is that of creating a cleaning device that can be used in particular in a calcining system to clean an exhaust gas flow, by means of which cleaning device a raw gas flow laden with contaminants can be cleaned efficiently and preferably substantially without the feeding of external fuel. This problem is solved in that the cleaning device comprises the following: a catalyst device for treating the raw gas flow; a gas feed, by means of which a raw gas flow to be cleaned can be fed to the catalyst device; a gas discharge, by means of which a clean gas flow obtainable by treating the raw gas flow can be led away, wherein the cleaning device comprises a heat exchanger, which thermally couples the gas feed and the gas discharge to each other such that heat, in particular heat released in the cleaning device, can be transferred from the clean gas flow to the raw gas flow.

Description

Cleaning device, calciner and method for purifying a raw gas stream

The present invention relates to a cleaning device, which can be used in particular in a calcining plant for purifying an exhaust gas flow. For example, in the calcination process for the production of cement clinker pollutants can be created or released by the combustion of fuels, especially inexpensive alternative fuels, and / or by the actual calcination, in particular oxidizable pollutants, such as carbon monoxide (CO) and / or volatile hydrocarbons (volatile organic Compound, VOC), and nitrogen oxides (NO _x ). These pollutants are preferably removed by means of a cleaning device autothermally from the exhaust stream before the exhaust stream is discharged to the environment.

A purification of the crude gas stream (exhaust gas stream) can be carried out, for example, by means of selective non-catalytic reduction, selective catalytic reduction, catalytic oxidation and / or a combustion apparatus.

The object of the present invention is to provide a cleaning device by means of which a crude gas stream laden with impurities can be cleaned efficiently and preferably without expenditure or at least small amounts of external energy.

This object is achieved according to the invention by a cleaning device for purifying a crude gas stream, in particular an exhaust gas stream of a calcining plant, the cleaning device comprising:

a catalyst device for treating the raw gas stream;

a gas supply, by means of which a crude gas stream to be purified can be fed to the catalyst device; a gas discharge, by means of which a clean gas flow obtainable by treatment of the crude gas stream can be discharged,

wherein the cleaning device comprises a heat exchanger, which thermally couples the gas supply and the gas discharge with each other, so that heat from the clean gas flow is transferable to the raw gas stream. In particular, by means of the heat exchanger, a heat energy supplied during the treatment of the raw gas stream in the cleaning device, resulting and / or released and at least partially entrained by the clean gas flow can be transferred to the raw gas stream. In a preferred embodiment, at least some of the reaction heat released by at least partial oxidation of the oxidizable constituents of the crude gas stream, in particular the oxidizable pollutants entrained in the crude gas stream, and at least partially transferred to the raw gas stream can be transferred by the clean gas stream. Through the targeted recycling of the released by oxidation of the oxidizable pollutants of the raw gas stream, the cleaning device allows the use of alternative and cost-effective fuels for carrying out the calcining process despite potentially increased and possibly fluctuating emission of oxidizable pollutants in the raw gas stream or exhaust stream.

The cleaning device is preferably used for cleaning flue gas, in particular dedusted flue gas in the low-temperature range,

especially in a so-called tailend system. A "tailend system" is understood to mean, in particular, the arrangement of the cleaning device downstream of a dedusting plant, in particular a dust filter system (eg a tissue, cloth or paper filter station) in the exhaust system of a plant oxidizable pollutants of the raw gas or exhaust gas released energy, the cleaning device combines the benefits of a long life and low cleaning costs of a catalyst with the low investment cost for a moderate catalyst volume by operating in a reaction-optimized temperature range between 250 - 600 ° C, preferably between 320 - 420 ° C and thereby avoids in particular low-temperature side reactions of substances contained in the flue gas with other substances contained in the flue gas or the flue gas supplied.

Preferably, the cleaning device is a flue gas cleaning device.

Preferably, the energy contained in the flue gas is usable by oxidation of oxidizable materials and by subsequent heat coupling, in particular for heating a raw gas stream formed by flue gas,

especially in the outflow of a fabric filter.

The crude gas stream is preferably flue gas, in particular dedusted flue gas. The dedusting of the flue gas is usually achieved with a commercially available fabric filter. Depending on the mode of operation, a typical temperature range for commercial fabric filters is between 100 and 280 ° C., in particular between 150 and 250 ° C., preferably between 180 and 220 ° C.

By virtue of the fact that the cleaning device comprises a heat exchanger for thermal coupling of the gas supply to the gas discharge, the cleaning device can preferably be operated in an energy-efficient manner, in particular in order ultimately to purify the raw gas stream laden with impurities efficiently and without supplying external energy.

It may be favorable if the cleaning device comprises a supply device for supplying an additive to the raw gas stream.

The additive may be, for example, ammonia (NH ₃ ) or ammonia (NH ₃ ) or an ammonia-forming material (eg, urea).

It can be provided that the additive comprises or is formed by an ammonia-air mixture and / or an ammonia-water mixture. The feed device is preferably arranged upstream of the catalyst device.

By means of the feed device supplied additive is thus supplied in particular mixed together with the crude gas stream to the catalyst device.

For example, the delivery device may include one or more nozzles for injecting or otherwise delivering the additive to the raw gas stream. The nozzles may be arranged, for example, in a matrix.

In particular, it can be provided that the supply device comprises a nozzle grid.

The catalyst device preferably comprises a DeNO _x catalyst for nitrogen oxide reduction. A DeNO _x catalyst may comprise, for example, titanium dioxide, vanadium pentoxide, tungsten dioxide and / or zeolite for the reduction of nitrogen oxides (NO _x ).

Alternatively or additionally, it can be provided that the

Catalyst device, an oxidation catalyst for the oxidation of

Contains impurities in the raw gas stream.

For example, the catalyst device may comprise an oxidation catalyst for the oxidation of carbon monoxide (CO) and / or hydrocarbons (HC).

Hydrocarbons (HC) are especially volatile hydrocarbons (VOC).

An oxidation catalyst of the catalyst device is preferably disposed downstream of a DeNO _x catalyst of the catalyst device. It may be favorable if the cleaning device comprises a mixing device.

By means of the mixing device is preferably an upstream of the

Catalyst device guided gas stream miscible. In particular, it may be provided that the gas stream comprises the crude gas stream, one or more additives and / or air and is miscible by means of the mixing device.

It may be favorable if the cleaning device both a feed device for supplying ammonia, ammonia-forming and / or ammonia-releasing material to the raw gas stream and a

DeNO _x catalyst for nitrogen oxide reduction comprises. The cleaning device then comprises in particular a device for selective catalytic reduction.

Alternatively or additionally, it can be provided that the

Cleaning device comprises a device for selective non-catalytic reduction, which, for example, by a feeding device for supplying ammonia, ammonia-forming and / or ammonia-releasing material to the raw gas stream and a

Combustion device comprises.

In a device for selective catalytic reduction, the nitrogen oxide reduction is preferably carried out on a catalyst surface. In a device for selective non-catalytic reduction takes place the

Nitrogen oxide reduction, especially in a combustion chamber of

Combustion device. Ammonia is preferably used as an aid for nitrogen oxide reduction.

In this description and the appended claims becomes

Nitrogen oxide reduction in particular referred to ammonia. It can However, alternative additives may be provided which (CH ₄ N ₂ 0) include, for example, urea, caffeine (C ₈ H i ₀ N ₄ O ₂₎ and / or other nitrogen-containing reducing agent.

The cleaning device according to the invention makes it possible, preferably, to use a calorific value in which an energy content of substances contained in the raw gas stream can be used for operating the cleaning device, in particular for heating one or more emission reduction processes.

It can be advantageous if the cleaning device comprises a dilution device for diluting the raw gas stream with air.

The dilution device is preferably upstream of the

Catalyst device angeord net.

Preferably, the dilution device is disposed downstream of a supply device for supplying an additive to the raw gas stream.

The terms "upstream" and "downstream" refer in particular to the flow direction of the crude gas stream or of the clean gas stream obtained by purification of the crude gas stream within the cleaning device and / or the entire calcination plant.

It may be favorable if the cleaning device comprises a mixing device.

The M ischvorrichtung is for example a plate by several baffle, U mlenkelemente and / or other turbulence generator formed gas mixer.

It can be advantageous if the mixing device downstream of a feed device and / or a dilution device of the cleaning device is arranged angeord net. Alternatively or additionally, it may be provided that the mixing device is arranged upstream of a catalyst device of the cleaning device.

In one embodiment of the invention can be provided that the

Treatment of short-chain, catalytically difficult to oxidize constituents of the crude gas stream, such. Methane, the cleaning device a

Combustion device comprises. This combustion device enables the operation of the cleaning device at a more energetically efficient, lower temperature level.

The combustion device may include, for example, a regenerative thermal combustion device (RTO).

The combustion device is preferably a heating device by means of which the gas stream to be treated can be heated using additional fuel, in particular to temperatures of at least approximately 800 ° C, for example at least approximately 900 ° C.

The combustion device is preferably downstream of

Catalyst device of the cleaning device arranged.

Furthermore, it can be provided that the combustion device is arranged upstream of a heat exchanger of the cleaning device.

It may be favorable if the combustion device comprises two heat storage sections, between which in particular a combustion chamber of the combustion device is arranged.

The heat storage sections preferably comprise a shaped body or a bed of a medium with a high heat storage capacity, for example ceramic. Preferably, the combustion device can be operated in a reverse operation, so that the heat storage sections and the combustion chamber arranged between the heat storage sections can be flowed through with varying time in optionally opposite flow directions.

In particular, it can be provided that the combustion device comprises a switching device or that the combustion device is associated with a switching device. By means of a switching device, the flow direction of the combustion device can be reversed, in particular if required.

The combustion device is preferably for the combustion of impurities, for example methane.

The cleaning device according to the invention is particularly suitable for use in a calcination plant, in particular for or when using alternative favorable fuels with increased raw emissions than

Primary energy source for the calcination process.

The present invention therefore also relates to a calcining plant, in particular for cement production, which comprises a cleaning device according to the invention.

The cleaning device is used in particular for the purification of exhaust gas of the calcining plant before it is discharged to an environment.

The cleaning device is preferably arranged with respect to a flow direction of the exhaust gas between a separation device, such as a fabric filter, and a chimney or chimney of calcining. The calciner preferably comprises a cement calciner (calciner) and a precalciner (precalciner).

A calciner is in particular a rotary kiln in which a cement raw material, in particular limestone, sand, iron ore and / or gypsum is burned to cement clinker.

A precalciner in particular comprises one or more heated classifiers for the pretreatment and / or drying of the raw materials.

In this specification and the appended claims, calcination is illustrated by the example of cement production.

Basically, "calcination" or "calcination" is to be understood as meaning the heating of solid substances for dewatering and / or decomposing them. The calcination can, for example, for the production of

Cement, alumina, calcium oxide, petroleum coke, etc. may be provided.

Preferably, a calcination process is carried out in countercurrent. A hot gas stream used for heating the solid is in this case preferably guided counter to a conveying direction of the solid.

The present invention is based on the further object of providing a method for purifying a crude gas stream which can be carried out efficiently and preferably substantially without the supply of external energy.

This object is achieved according to the invention by a method for purifying a crude gas stream, in particular an exhaust gas stream of a calcining plant, the method comprising:

Supplying a raw gas stream to be purified to a catalyst device; Treating the crude gas stream by means of the catalyst device, so that a clean gas flow is obtained; Transfer of heat by means of a heat exchanger from the clean gas flow to the raw gas stream to be supplied to the catalyst device.

The process according to the invention preferably has one or more of the features and / or advantages described in connection with the cleaning device according to the invention and / or the calcination plant according to the invention.

Furthermore, the cleaning device according to the invention preferably has one or more of the features and / or advantages described in connection with the calcining plant according to the invention and / or the method according to the invention.

The inventive method allows in particular that the

Calcining plant for carrying out a calcination process alternative or cheaper fuels are provided or supplied as a primary energy source and / or a process for providing the thermal energy to perform a calcining process is operated such that an outflowing from the calcination plant raw gas or exhaust gas flow such increased and / or fluctuating Concentration of oxidizable constituents or pollutants may have, which before a

Release into an ambient air a cleaning measure in one

Cleaning device can be advised or even required, whereby the current operating costs of calcining can be advantageously reduced.

In addition, it can be provided that the calcination plant according to the invention has one or more of the features and / or advantages described in connection with the cleaning device according to the invention and / or the method according to the invention. It may be favorable if the cleaning device and / or the calcination plant is designed and set up such that the invention

Method is feasible.

In particular, it can be provided that the cleaning device and / or the calcination plant comprises a control device, by means of which the

Cleaning device or the calcining plant for carrying out the method according to the invention is controllable.

It may be favorable if the temperature of the crude gas stream, which is supplied by means of the gas supply to the catalyst device, upstream of the heat exchanger has a temperature of less than 320 ° C.

It may be favorable if the raw gas stream to be purified by means of

Heat exchanger is heated to a temperature of at least about 250 ° C, for example at least about 300 ° C, in particular at least about 320 ° C.

Alternatively or additionally, it may be provided that the crude gas stream to be purified is heated by means of the heat exchanger to a temperature of at most approximately 500 ° C., for example at most approximately 450 ° C., for example at most approximately 420 ° C.

It can be advantageous if an additive is supplied to the crude gas stream. An amount of the added additive is preferably controlled as a function of a nitrogen oxide concentration of the raw gas stream flowing in the catalyst device, and preferably of one

Nitrogen oxide and ammonia concentration of the catalyst stream leaving the gas stream.

In particular, it can be provided that a flow rate of the

Gas stream and / or a nitrogen oxide concentration of the in the Katalysatorvor- Direction incoming gas flow is measured and compared with one or more setpoints.

In particular, a comparison of actual values and desired values can be provided at an inlet region of the catalytic converter device and / or at an outlet region of the catalytic converter device.

In one embodiment of the invention can be provided that dilution air is supplied to the raw gas stream. An amount of the supplied dilution air is preferably regulated as a function of a temperature of the gas stream leaving the catalyst device.

In particular, a temperature of at most about 420 ° C, in

special cases 500 ° C, provided at an outlet region of the catalyst device.

The gas stream is preferably mixed by means of a mixing device, in particular upstream of the catalyst device.

It may be favorable if the additive and / or the dilution air is preheated using heat from the catalyst device.

Alternatively or additionally, it can be provided that the additive and / or the dilution air is preheated using heat from a combustion device, in particular a regenerative thermal combustion device.

It may be favorable if the catalyst device leaving the

Gas stream of a combustion device, in particular a regenerative thermal combustion device supplied, and preferably to a temperature of at least about 750 ° C, for example at least about 900 ° C, heated. In this way, in particular a reliable methane depletion can be achieved with energy-efficient operating temperature of the cleaning device.

It can be advantageous if the raw gas stream is an offgas stream of one or more precalciner of a calcining plant.

It may be favorable if the crude gas stream before being supplied to the cleaning device, in particular before being fed to the heat exchanger, is cleaned by means of a separating device, for example freed from dust and suspended matter. The separating device can be, for example, a filter device, in particular a fabric filter.

It may be favorable if the raw gas stream to be cleaned by means of the cleaning device is pre-cleaned before being fed to the cleaning device, in particular at a temperature of less than approximately 350 ° C., for example less than approximately 320 ° C.

The raw gas stream to be purified by means of the cleaning device preferably comprises substantially exclusively gaseous impurities which are removed and / or converted by means of the cleaning device.

The inventive method can be carried out in particular on a cleaning device according to the invention.

The present invention therefore also relates to the use of a cleaning device according to the invention for carrying out the method according to the invention.

Furthermore, the cleaning device according to the invention, the calcination plant according to the invention and / or the process according to the invention can be individual or more of the features and / or advantages described below:

The cleaning device is preferably arranged in the wake of a precalciner.

The crude gas stream to be purified preferably comprises carbon monoxide (CO), which can be reacted to heat the crude gas stream, in particular by means of the oxidation catalyst.

The DeNOx catalyst is preferably used for the chemical reaction of nitrogen oxides with ammonia to nitrogen and water, in particular

Steam.

The oxidation catalyst is preferably used to convert carbon monoxide with oxygen to carbon dioxide. In this case, in particular heat is released, which can be used to operate the cleaning device, in particular in order to increase the energy efficiency of the cleaning device and to allow operation without supply of external fuel.

Preferably, heat is generated by catalytic oxidation of carbon monoxide (CO), which is transferable by means of the heat exchanger to the raw gas stream flowing into the cleaning device.

Preferably, an optimum inlet temperature of the raw gas stream at the inlet of the catalyst device is between about 320 ° C and about 420 ° C.

The exit temperature is preferably about 420 ° C.

A temperature increase within the catalyst device preferably results from exothermic catalytic conversion of pollutants of the crude gas stream, in particular carbon monoxide (CO). The heat generated in the cleaning device, in particular a residual energy released by catalytic oxidation of the carbon monooxide, can be used, for example, in an energy recovery process, in particular an Organic Rankine Cycle or Kalina process for generating electricity. Alternatively or additionally, use of the heat for preheating the dilution air may be provided.

The invention can be implemented in particular while avoiding costly remodeling work on an already existing calcining plant.

Preferably, a fuel requirement of the cleaning device and / or the calcination plant can be reduced by using energy contained in the crude gas stream.

Preferably, the amount of carbon dioxide emitted can be reduced by reducing the amount of fuel required.

The heat for heating the raw gas stream is preferably in one

Reactor (especially in the catalyst device) can be provided.

It may be favorable if an inlet temperature of the catalyst device can be adapted by varying and / or varying the carbon monooxide content of the crude gas stream.

The invention preferably allows the saving of investment costs and the reduction of the greenhouse gas methane.

Further preferred features and / or advantages of the invention are the subject of the following description and the drawings of exemplary embodiments. In the drawings show:

Fig. 1 is a schematic representation of a calciner for cement production;

Fig. FIG. 2 is a schematic representation of a cleaning device of FIG

calcining plant;

Fig. FIG. 3 is a schematic illustration, corresponding to FIG. 2, of an alternative embodiment of a cleaning device in which a combustion device is provided; FIG. and

Fig. 4 a of FIG. 3 corresponding schematic representation of

Cleaning device of FIG. 3, with an alternative

Flow guidance is provided.

Identical or functionally equivalent elements are provided with the same reference numerals in all figures.

One in Fig. 1 illustrated embodiment of a designated as a whole with 100 calcining used, for example, the production of cement.

For this purpose, the calcining plant 100 comprises a mill device 102 (also called a raw mill) for grinding raw materials, for example limestone, clay, sand, iron ore and / or gypsum. The calciner 100 further includes a precalciner 104 formed of a plurality of classifiers 106 and a calciner 108, which is particularly constituted by a rotary kiln 110.

The calcining plant 100 further comprises a cooling device 112 as well as a separation device 114 and a chimney 116. The cooling device 112 serves to cool the material treated by means of the precalciner 104 and the calciner 108.

The separation device 114 serves to separate impurities, in particular solids, from an exhaust gas stream of the calcination plant 100.

The chimney 116 serves to deliver the purified exhaust gas flow to the environment.

The calcining plant 100 further comprises a cleaning device 118 for additional purification of the exhaust gas flow.

The cleaning device 118 will be described below with reference to FIGS. 2 to 4 discussed in more detail.

The calcining plant 100 works in particular as follows:

Raw materials are supplied via the mill device 102. These raw materials are then supplied via a solids line 120 of the calciner 100 gradually to the precalciner 104, the calciner 108 and finally the cooling device 112. In this case, the raw materials are converted by the action of heat, so that cement clinker is formed, which is finally cooled down by means of the cooling device 112. The

For example, heat to convert the raw materials into cement clinker may be produced by combusting fuels, preferably alternative, inexpensive fuels.

By means of a gas line 122 of the calcining plant 100, a gas stream, in particular air, is passed through the calcining plant 100 substantially counter to a conveying direction of the materials to be treated.

In particular, a gas stream is passed through the cooling device 112, the rotary kiln 110, the precalciner 104 and / or the mill device 102. carried out. The gas stream is thereby loaded with impurities, which must be deposited or converted to a discharge of the

Gas flow to the environment to allow.

In particular, by means of the separation device 114, which comprises, for example, a filter device 124, solids are separated from the gas stream.

Further purification of the gas stream is carried out by means of a cleaning device 118.

An embodiment of a cleaning device 118 is shown for example in FIG. 2 shown.

The gas stream to be cleaned by means of the cleaning device 118 is referred to below as the raw gas stream.

As can be seen from FIG. 2, the cleaning device 118 comprises a gas feed 126, a gas discharge 128 and a catalyst device 130.

By means of the gas feed 126, the raw gas stream can be fed to the catalyst device 130.

By means of the catalyst device 130, the crude gas stream can be cleaned, so that a clean gas flow is available, which can be discharged by means of the gas outlet 128, in particular to the chimney 116, can be supplied.

The gas supply 126 and the gas discharge 128 are thermally coupled to one another by means of a heat exchanger 132, so that heat can be transferred from the gas discharge 128 to the gas supply 126. In particular, the raw gas stream supplied via the gas feed 126 can thus be heated using heat from the clean gas stream discharged by means of the gas discharge 128.

The catalyst device 130 of the cleaning device 118 comprises one or more catalysts.

In particular, the catalyst device 130 preferably includes a DeNOx catalyst 134 and / or an oxidation catalyst 136.

The DeNOx catalyst 134 is used in particular the nitrogen oxide reduction.

For this purpose, the DeNO _x catalyst 134 cooperates with a supply device 138 for supplying ammonia or urea.

The delivery device 138 is relative to a flow direction of the

Gas stream in the cleaning device 118 upstream of the catalyst device 130 is arranged.

For example, the feed device 138 comprises a nozzle grid for injecting an ammonia-air mixture or an ammonia-water mixture into the raw gas stream.

Catalytic coating of the DeNO _x catalyst 134 allows chemical reaction of the ammonia or urea with the nitrogen oxide contained in the raw gas stream, resulting in conversion to nitrogen and water.

The oxidation catalyst 136 is particularly useful for the conversion of hydrocarbons and other carbonaceous or other

combustible substances. Preferably, the oxidation catalyst 136 serves to convert carbon monoxide to carbon dioxide. This reaction is exothermic so that heat can be provided by means of the oxidation catalyst 136.

The cleaning device 118 preferably further comprises a dilution device 140, by means of which in particular air to the

Raw gas stream can be supplied.

The dilution device 140 is in particular arranged downstream of the feed device 138 and upstream of the catalyst device 130.

Finally, the cleaning device 118 also comprises a mixing device 142, by means of which the added additive, the supplied dilution air and / or the crude gas stream can be mixed with one another.

The mixing device 142 is in particular downstream of the dilution device 140 and preferably the delivery device 138 as well

upstream of the catalyst device 130.

The cleaning device 118 operates as follows:

The raw gas stream to be purified by means of the cleaning device 118 is preferably supplied at low temperature, in particular less than 320 ° C., via the gas feed 126. This low temperature results in particular by the previous cleaning by means of the separation device 114, since in this case a low temperature may be desirable.

For efficient cleaning of the crude gas stream by means of the cleaning device 118, a higher temperature is to be preferred. In particular, one is

Temperature of at least about 320 ° C at the inlet of the catalyst direction 130 to ensure the desired catalytic processes and preferably to avoid unwanted side reactions.

The initially too cold crude gas stream must therefore be heated prior to its supply to the catalyst device 130. This is done in particular by means of the heat exchanger 132 using heat of the clean gas flow.

During operation of the cleaning device 118, the inlet temperature of the catalyst device 130 is above 320 ° C, so that the catalytic processes take place and in particular carbon monoxide is converted by means of the oxidation catalyst 136 with heat release. This heat output leads to an increase in temperature of the gas flow passed through the catalyst device 130, so that the clean gas flow, which is discharged via the gas outlet 128, may have a higher temperature than the raw gas flow supplied via the gas supply 126.

By means of the heat exchanger 132, the heat released by the exothermic reaction of carbon monoxide can thus be used to heat up the supplied raw gas stream.

For commissioning the cleaning device 118, a separate (not shown) burner device may be provided, in particular to initially heat the crude gas stream and to start the catalytic processes until the process can be continued self-sustaining.

For depletion of methane, the cleaning device 118 can be brought to a necessary for the oxidation catalyst higher operating temperature of preferably 500 ° C. For this operating design, a catalyst suitable for the NOx reduction is preferably used. One in FIGS. 3 and 4 differs from the embodiment shown in FIG. 2 substantially in that a combustion device 144 is provided. This combustion device 144 essentially serves to design the catalytic converter device 130 under the lower operating temperature, which is better adapted for selective catalytic NOx reduction and CO oxidation, with a maximum outlet temperature of 420 ° C. and thus better utilization of the released energy above the latter

Oxidation catalyst.

The combustion device 144 is designed in particular as a regenerative thermal combustion device 146.

The combustion device 144 preferably includes two heat storage sections 148, between which a combustion chamber 150 with a burner device 152 is disposed.

A switching device 154 allows the combustion device 144 to flow through in opposite directions. By means of the switching device 154 can be selected in particular, which of the two heat storage sections 148 of the discharged from the catalyst device 130 gas stream is supplied. The clean gas flow is then removed via the respective other heat storage section 148.

The alternating flow through the combustion device 144 serves, in particular, to provide the high temperatures prevailing in the combustion chamber 150 during operation of the combustion device 144 as energy-efficiently as possible. For this purpose, the heat contained in the outflowing gas stream is at least partially stored in a heat storage section 148. This heat is then transferred to the inflowing gas stream after a switching operation by means of the switching device 154, in order to preheat this prior to its supply to the combustion chamber 150. The combustion device 144 is used in particular for the combustion of hydrocarbons, for example methane.

The combustion device 144 is preferably controlled depending on a determined methane concentration. In addition, a control of the cleaning device 118 may be provided for varying the additive supplied by means of the feed device 138. In particular, the feed of the additive may be controlled depending on a concentration of nitrogen oxide upstream and / or downstream of the catalyst device 130.

In addition, by means of a control of the dilution device 140, a desired temperature at the inlet of the catalyst device 130 can preferably be set.

Incidentally, the embodiment of a cleaning device 118 illustrated in FIGS. 3 and 4 is identical in construction and function to the one shown in FIG. 2 embodiment, so that on the above

Description insofar reference is made.

In a in Figs. 2 to 4 not explicitly shown

Embodiment variant of a cleaning device 118 according to the invention, the heat exchanger 132 may comprise at least one bypass line. In this case, "having a bypass line" should both be understood that the heat exchanger 132 itself has this bypass line or is provided with this, in particular that the bypass line on or in

Heat exchanger is designed or arranged, as well as that of

Heat exchanger 132 by a the input side gas supply 126 with the output side raw gas guide connecting or the input side clean gas duct with the output side gas discharge 128, from

Heat exchanger 132 separated bypass line can at least be flowed around by a part of the incoming raw or clean gas. The bypass line ensures in particular that the flowing through them part of the Raw or clean gas stream can not participate in the heat exchange process in the heat exchanger 132 or participates.

In a preferred variant, the at least one bypass line is designed to be controllable and / or controllable with regard to a flow. For this, the bypass line may include at least one flow restriction means, e.g. an adjustable flap, throttle, orifice and / or valve as passive with respect to the flow of the actuating means and / or a fan or fan as the active actuating means, have. In this variant, the heat exchange process can be set in the heat exchanger 132 in a simple manner and advantageously a cleaning performance of the cleaning device 118, in particular the

Catalyst device 130 can be optimized.

Claims

claims

A cleaning device (118) for cleaning a raw gas stream, in particular an exhaust stream of a calcination plant (100), wherein the cleaning device (118) comprises:

a catalyst device (130) for treating the raw gas stream;

a gas supply (126), by means of which a raw gas stream to be purified can be fed to the catalyst device (130);

a gas discharge (128), by means of which a clean gas stream available by treatment of the crude gas stream can be discharged, characterized in that the cleaning device (118) comprises a heat exchanger (132) which thermally couples the gas supply (126) and the gas discharge (128) to one another that heat from the clean gas stream is transferable to the raw gas stream.

2. Cleaning device (118) for purifying an exhaust gas stream of a calcining plant (100) according to claim 1, characterized in that the cleaning device (118) favors or enables the use of alternative, less expensive fuels for the calcination plant (100), in particular a calciner (108 , 110) the

Calcining plant (100) with alternative, less expensive fuels, is operated or operated, which is a more incomplete

May have combustion and increased and / or

fluctuating concentration of oxidizable constituents or pollutants in the exhaust stream of Kalizinieranlage (100), in particular the calciner (108, 110) can expect or have.

3. Cleaning device (118) according to claims 1 and 2, characterized in that in the gas supply (126) of the Cleaning device (118) supplied raw gas stream a first

Concentration of oxidizable constituents or pollutants and an inlet temperature of up to 280 ° C, and the

Cleaning device (118) one in the oxidizable constituents or pollutants of the crude gas stream in the gas supply (126) by their chemical reaction, in particular oxidation, released

Reaction heat utilizes, by means of the heat exchanger (132), the temperature of the raw gas stream at an input side of the

Catalyst device (130) favorable for a catalytic conversion of the pollutants of the crude gas stream

Setting the catalyst inlet temperature, wherein the heat exchanger (132) by means of the catalyst device (130) leaving, catalytically purified gas stream is fed so that the cleaning device (118) can be operated substantially without supply of external energy or is.

4. Cleaning device (118) according to one of the preceding

Claims, characterized in that the heat exchanger (132) has or is provided with at least one, preferably in a flow controllable or controllable bypass line, so that a part of the over the gas supply (126) inflowing raw gas stream and / or a part of via the gas discharge (128) flowing clean gas flow can pass through the heat exchanger (132) such that the respective part of the raw gas flow and / or the clean gas flow is not involved in a heat exchange process in the heat exchanger (132)

can participate or participate.

5. Cleaning device (118) according to one of the preceding

Claims, characterized in that the cleaning device (118) comprises a feed device (138) for supplying an additive, in particular ammonia (NH ₃ ), to the raw gas stream.

6. Cleaning device (118) according to one of claims 1 to 5, characterized in that the catalyst device (130) has a DeNO _x catalyst (134) for nitrogen oxide reduction and / or an oxidation catalyst (136) for the oxidation of carbon monoxide ( CO), hydrocarbons (HC) and / or other combustible substances.

7. cleaning device (118) according to one of claims 1 to 6,

characterized in that the cleaning device (118) comprises a dilution device (140) for diluting the crude gas stream with air.

8. Cleaning device (118) according to one of claims 1 to 7,

characterized in that the cleaning device (118) comprises a mixing device (142), by means of which the following is miscible: at least one additive, dilution air and / or the raw gas stream.

9. cleaning device (118) according to one of claims 1 to 8,

characterized in that the cleaning device (118) comprises a combustion device (144), in particular a regenerative thermal combustion device (RTO) (146).

10. calcining plant (100), in particular for cement production, comprising a cleaning device (118) according to one of claims 1 to 9.

11. A method for purifying a raw gas stream, in particular one

Exhaust gas stream of a calcination plant (100), the method

Includes:

Supplying a raw gas stream to be purified to a catalyst device (130);

Treating the crude gas stream by means of the catalyst device (130), so that a clean gas flow is obtained; Transfer of heat by means of a heat exchanger (132) from the clean gas flow to the raw gas stream to be supplied to the catalyst device (130).

A method according to claim 11, characterized in that the

Calcination plant (100) for carrying out a calcination process alternative or cheaper fuels are provided or supplied as a primary energy source and / or a process for

Providing the thermal energy to carry out a

Calcining process is operated such that one of the

Calcining plant flowing off crude gas or exhaust gas flow such an increased and / or fluctuating concentration of oxidizable

Ingredients or pollutants, that before release an ambient air a cleaning measure in one

Cleaning device (118) may be required.

13. The method according to any one of claims 11 or 12, characterized

characterized in that the cleaning device (118) utilizes a heat of reaction liberated in the oxidisable constituents or pollutants of the crude gas stream in the gas feed (126) and in the

Essentially without supply of external energy is operated.

14. The method according to any one of claims 11 to 13, characterized

characterized in that the crude gas stream to be purified is heated by the heat exchanger (132) to a temperature of at least approximately 320 ° C and / or to a temperature of at most approximately 420 ° C.

15. The method according to any one of claims 11 or 14, characterized

characterized in that an additive is supplied to the crude gas stream, wherein an amount of the supplied additive is preferably controlled in dependence on a nitrogen oxide concentration of the catalyst device (130) leaving the gas stream.

16. The method according to any one of claims 11 to 15, characterized in that dilution air is supplied to the raw gas stream, wherein an amount of the supplied dilution air is preferably controlled as a function of a temperature of the

Catalyst device (130) leaving the gas stream.

17. The method according to any one of claims 11 to 16, characterized

in that an additive and / or dilution air and / or the raw gas stream are mixed together by means of a mixing device (142).

18. The method according to any one of claims 11 to 17, characterized

characterized in that the additive and / or the dilution air is preheated using heat from the catalyst device (130).

19. The method according to any one of claims 11 to 18, characterized

characterized in that the additive and / or the dilution air using heat from a combustion device (144), in particular a regenerative thermal

Combustion device (146) is preheated.

20. The method according to any one of claims 11 to 19, characterized

characterized in that the gas stream leaving the catalyst device (130) is fed to a combustion device (144), in particular a regenerative thermal combustion device (146), and is preferably heated to at least approximately 900 ° C.

21. The method according to any one of claims 11 to 20, characterized

in that the raw gas stream is an exhaust gas stream of a

Precalciner (104) of a calcining plant (100).

22. Use of a cleaning device (118) according to one of claims 1 to 9 for carrying out a method according to one of claims 11 to 21.

Use of a method according to one of claims 11 to 21 for operating a calcining plant (100), in particular according to claim 10.