DE102010054648A1 - Material flow i.e. air, drying and/or warming up method for length-variable hot gas generator of hot gas burner, involves adapting length of generator to determined heat requirement, and determined quantity, quality and temperature of flow - Google Patents

Abstract

The method involves supplying and combusting high calorific fuel (6). A heat requirement for treatment of a material flow (10) is determined. A quantity, a quality and a temperature of the material flow is determined. A length of a hot gas generator (1) is adapted to the determined heat requirement, and the determined quantity, quality and temperature. A quantity or a type of the fuel is adapted based on the determined heat requirement. A combustion temperature for a process is manually or automatically varied. A state of the material flow is determined. An independent claim is also included for a hot gas generator comprising a mixing chamber.

Description

The invention relates to a method and an apparatus for drying and / or warming up a material stream by means of a hot gas generator.

Hot gas generators with a burner device are generally used for upgrading process gases or other material streams for subsequent processes. The use of hot gas generators is particularly advantageous when existing low calorific process fuels are used.

In particular, the use of hot gas generators from the smelting process of iron ores is known. In the smelting of iron ores in the blast furnace process gaseous products, which are well known under the name "gassing gasses" and which to a certain extent of combustible components (CO, H ₂ ), but for the most part of inert gaseous components (CO ₂ , N ₂ ) exist. Likewise, dried coal can be used as fuel.

The so-called "pulverized coal injection", in which coal is injected directly into the blast furnace, thus the resulting process gas, namely the blast furnace gas, as well as the source material, namely the coal, can be used as an energy source.

The hot gas generator can be combined directly with a combustion process and thus leads to an efficient energetic use of the already reached high temperature level.

Therefore, such hot gas generators are used to dry and / or heat other gases. In particular, an application in the field of the power plant industry (eg as a channel burner and as a booster before turbines) comes into consideration.

So far, it has been desired that hot gas generators are designed to be as short as possible to dry and / or warm up of a stream. Here, the construction cost, the volume of construction and thus also the necessary heat input were kept small. Notably, these known devices are set up for optimal process flow. A disadvantage of the known devices is that the streams, which are sometimes subject to strong fluctuations, lead to uneven degrees of drying and temperatures of the respective streams at the output of the devices.

In the known hot gas generators also a predetermined at the operating point of the associated blast furnace design was made. However, it has been found that even small deviations in the environmental conditions have significant effects on the result of the treatment of the gases to be heated or dried. Therefore, there is now a desire to allow the operation of such hot gas generators so that these effects of changing environmental conditions can be reduced or even avoided.

On this basis, it is an object of the present invention, at least partially solve the problems described with reference to the prior art. In particular, a method for drying and / or warming of a stream by means of a hot gas generator is to be specified, which certainly achieves the desired effects, in particular a demand-oriented real-time monitoring or regulation of the processes is made possible. Likewise, a hot gas generator is to be specified, which is just suitable for the use of such a method.

These objects are achieved by a method according to the steps of claim 1 and a hot gas generator according to the features of claim 8. Further advantageous embodiments and fields of application of the invention are specified in the dependent formulated claims. The features listed individually in the claims can be combined with one another in any technologically meaningful manner and can be supplemented by explanatory facts from the description, wherein further embodiments of the invention are shown.

• a) Zuführen und Verbrennen zumindest eines Brennstoffs;
• b) Bestimmen eines Wärmebedarfs zur Behandlung des Stoffstroms; und
• c) Anpassen einer Länge des Heißgasgenerators an das Ergebnis aus Schritt b).

The process according to the invention for drying and / or warming up a stream of material is carried out by means of a variable-length hot gas generator, which is flowed through by a stream of material, the method comprising at least the following steps:

• a) supplying and burning at least one fuel;
• b) determining a heat requirement for the treatment of the material stream; and
• c) adjusting a length of the hot gas generator to the result of step b).

The individual method steps of the method according to the invention are iteratively repeated during the operation of the hot gas generator normally in the order given here in the manner of a loop. Some steps take place in parallel with other steps.

In common applications of the method for drying and / or heating a stream, such as. As the smelting process of iron ores, the treated with the hot gas generator material flow is then fed to other processes. For this purpose, it is desired that the material flow has a low absolute and relative humidity. Thus, it makes sense to heat the stream, whereby the absolute humidity, but at least the relative humidity is reduced. Through this drying process, the material flow is thus prepared in a suitable manner for subsequent processes.

The material flow is often air supplied from the environment. Depending on the weather conditions, the air has a relative humidity, temperature, quality and composition. Also, the material stream can be removed from other processes and fed to the drying by the hot gas generator according to the invention. Characteristic of usable material flows is that they are safe to be used as heating medium in downstream processes. This is especially relevant that the material flow is not combustible and / or combustion by z. B. high oxygen content is not intensified. An advantage of the process according to the invention is that the material stream does not have to be subjected to any pretreatment because the process can react or be adapted to fluctuations in the material stream, in particular with respect to water content, dust content, chemical composition, mass flow, temperature and / or the like.

This is achieved in particular by a suitably adapted operation of a variable-length mixing chamber of the hot gas generator. The hot gas generator regularly has a mixing chamber closed on one side, which has holes, slots or the like in its chamber wall in order to supply a hot, dry combustion gas to the environment. This combustion gas is generated by combustion of a fuel which is burned in a burner device with the supply of oxygen. The adaptation of the length of the hot gas generator can also take place by a change in the burner device in which this protrudes, for example, with a variable depth into the mixing chamber and thus changes the length of the hot gas generator. The combustion gas enters the hot gas generator and out through the holes in the chamber wall and / or slots between individual elements of the chamber wall into the environment. Due to the variability of the length of the hot gas generator, the distance traveled by the material flow when passing the hot gas generator can be reduced or extended. Thus, the heat input and the mixing of the combustion gas can be significantly influenced by the flow of material. Likewise, it is of course possible alternatively and / or cumulatively that the material flow enters through the chamber wall and is brought into contact there with the combustion gas. The contact between combustion gas and material flow is to be realized in such a way that a heat transfer from the hotter combustion gas to the colder and / or wetter material flow is ensured.

The hot gas generator is flowed through by a stream of material, which means in particular flows through and / or flows around. The material flow is usually supplied to the process from the environment and dried by contact with the combustion gas and heated. The material flow is characterized in particular by the fact that its composition, the fluctuations of the environment, eg. As the weather is subject. The processes in which the method according to the invention is switched on usually proceed in large halls which, due to their size and frequently open doors, are only slightly isolated from the external weather conditions. Therefore, it is necessary to heat and / or dry the stream even though it is supplied by other processes.

The hot gas generator has at least one burner device at one end of the mixing chamber, which burns a fuel (or optionally also a mixture of a plurality of fuels) by means of supplied oxygen (or air). The transition from the burner device to the hot gas generator can be carried out with a sleeve or the like. The combustion takes place practically exclusively in the burner device. This effectively prevents the material flow from directly influencing combustion. At least one partial area (eg near the burner area) of the hot gas generator preferably represents a separate area which allows constant conditions for the combustion of the at least one fuel with the oxygen. This portion of the hot gas generator also allows a good heat distribution of the selective heat input from the combustion in the burner device. Preferably, this portion is located just before the mixing chamber of the hot gas generator, so that the combustion gas is fed directly after the treatment of a material flow.

The at least one fuel may be a combustible gas, as is conventional natural gas or the like. But it can also be used for this purpose, liquid and solid fuels that burn gas in a suitable management of the combustion. Characteristic of this described group of fuels is that they have a high calorific value, ie are highly calorific. Thus, the method is particularly suitable for pulverized coal injection ("Pulverized Coal Injection"). In addition, high-calorie fuels such as methane (CH ₄ ) and hydrogen (H ₂ ) can be used.

Another fuel comes into consideration (in particular cumulatively) also a so-called "lean gas". The term "weak gas" will be based on the above mentioned gas above all, but this is not to be understood in the sense of a restriction. Characteristic of weak gases is that they have a low calorific value, ie are low-calorific. The term of the lean gas used in the context of this invention therefore relates to a range of the specific heat content or the heat density of a maximum of 1,200 kilocalories per standard cubic meter or a maximum of 5 megajoules per standard cubic meter. In addition to the purely molecular components such as carbon monoxide (CO), hydrogen (H ₂ ), carbon dioxide (CO ₂ ) and nitrogen (N ₂ ), the weak gases are loaded with a not inconsiderable amount of dust. In its main feature, a lean gas is hardly combustible.

The weak gases as "waste products" or by-products from a wide variety of processes have as main fuel carbon monoxide (CO). They usually have carbon monoxide levels of well below 45 vol .-%. The remaining portion consists almost exclusively of the nonflammable components carbon dioxide (CO ₂ ) and nitrogen (N ₂ ). However, a wide variety of gaseous organic compounds can still be present in the lean gas, which are combustible or non-combustible. The lean gases thus have in particular a very small proportion of combustible components.

The process for drying and heating of a stream allows now despite fluctuating input variables, such as water content and temperature of the supplied material flow, reliably provide a stream with desired properties (temperature, water content, etc.) for the downstream processes, because the drying process a heat demand of the drying process is adjusted. This is done in particular by an adaptation of the contact or mixing process or the heat transfer of combustion gas to the material flow. In particular, the space or the distance in the flow direction for the mixture or the heat transfer is changed (increased or decreased). This space or this distance is in this context determined in particular by the mixing chamber of the hot gas generator, which is designed here variable in length and thus can be extended and / or reduced accordingly.

In particular, this also real-time control for the drying process is achieved. A real-time control of the drying process has the advantage that the at least one fuel can be used in a suitable amount. Likewise, it can be achieved that the output variable (such as the temperature) of the material stream can be adjusted with significantly small deviations, in particular essentially independent of a corresponding (strongly) varying input variable of the material stream prior to contact with the hot gas generator. Also, the supply of the dried material flow can be used not only as a disturbance, but also as a control variable for the following processes.

The determination of a heat requirement is therefore based in particular on the state of the incoming material flow and / or the (desired) state of the outflowing material flow. For this purpose, a measurement and / or a calculation of properties (water content, dust content, chemical composition, mass flow, temperature and / or the like) of the incoming material stream and / or outgoing material stream can be used. To measure such a property corresponding sensors may be provided at a suitable location, the measurement results are included in the determination of the heat demand. Also indirect measurement methods such. B. Temperature measurement in conjunction with a material flow meter can be used to determine the heat demand. In addition, the heat requirement can be calculated using current and / or previous measured values, for example using a characteristic map integrated in a data processing program, which maps characteristic operating conditions for the operation of the hot gas generator.

In step c) of the method according to the invention, the result from step b), namely the (desired) specific heat requirement, is taken into account by adjusting a length of the hot gas generator.

Climb z. As the heat demand, the hot gas generator is extended and thus extends the distance to the entry of heat in the flow of material. If the heat demand drops, the hot gas generator can be shortened. The purpose of the extension or shortening of the hot gas generator is adapted to the heat demand heat supply, which causes a constant output heat of the material flow, regardless of the input heat. However, a changed output heat may also be desired if it is used as a control variable for a downstream process.

In a further advantageous embodiment of the method according to the invention, an amount of the material stream is determined before step c) (step b1)), and in step c) adjusting the length of the hot gas generator to the specific amount of the material flow.

To determine the amount of material flow, in particular flow-acting sensors are suitable. For example, a speed can be determined via a propeller, which corresponds to an amount of the material flow. Furthermore, a Prandtl tube can be used, which can determine a speed from the pressure difference between back pressure and ambient pressure. When used in known cross sections through which the material stream flows, these measuring devices can be used to determine the quantity.

Also, indirect determinations of the amount of material flow can be used, such. B. a flap position of a supply flap of the material flow, if the other flow values are known. Also, the measuring means can be used to determine the heat demand with simultaneous adjustment of the temperature, that is, a calorimeter or anemometer. Likewise, a calculation of the amount of material flow is possible here, as already explained above. The "amount" of the material flow means, in particular, a current and / or future value for the mass flow (or volume flow).

The amount of material flow is a particularly important parameter for determining the heat demand, so this is of particular importance in the regulated heat supply by means of the hot gas generator.

In a further advantageous embodiment of the method according to the invention, a quality of the material flow is determined before step c) (step b2)), and in step c) the adaptation of the length of the hot gas generator ( 1 ) to the specific quality of the material flow.

The determination of the quality of the material stream can be determined in particular optically. This z. B. Dust levels and (condensed) water contents are detected in their amount by changing the light transmittance. Alternatively or additionally, a heating element can be used which, similar to a calorimeter, allows conclusions as to the composition of the material flow due to current or temperature changes.

According to the aforementioned manner, the length of the hot gas generator can be adapted to the quality of the material flow. Also, the length of the hot gas generator is adjusted at several varying input variables so that the output variable, namely the degree of drying of the material flow is constant, or can be set as a control variable for downstream processes.

According to a further advantageous development of the method according to the invention, it is provided that a temperature of the material flow is determined before step c) (step b.3)), and in step c) adjusting the length of the hot gas generator to the specific temperature of the material flow.

The determination of the temperature of the material stream can be carried out using any conventional measuring means and / or a suitable calculation method. In order to generate a control signal of the length of the hot gas burner, a sensor is provided for determining the temperature of the material flow, which is operated on the basis of electric current and thus outputs electrical signals. Here, especially thermocouples, infrared cells and / or UV cells and generally sensors based on the Seebeck or Peltier effect can be used. The location of the measurement of the temperature of the material stream can be arranged both before entering into the mixing with the combustion gas and after mixing with the combustion gas. The measurement of the temperature of the stream before mixing with combustion gas may be useful, in particular, if the material flow has an additional effect on the process management, such. B. Cooling of mixing chambers of any kind.

Most preferably, the change in the length of the hot gas generator is changed as a function of the change of a single property of the inflowing material flow while maintaining an outflowing material flow having substantially constant properties regularly as follows: Change of the inflowing material flow Length of the hot gas generator Water content is increased extended Dust content is increased extended Amount (mass flow) we increased extended Temperature is increased shortened

If the property of the inflowing material flow changes in the opposite direction, then also opposite measures are required with the hot gas generator. An adaptation of the length is expediently carried out only if the change is significant, ie would change the properties of the outflowing material flow over a predetermined tolerance range.

In a further advantageous embodiment, depending on the result from step b), at least one quantity or one type of the at least one fuel is adapted. This step is also referred to below as step c.1). It is also possible that the amount and type of at least one fuel to be adjusted.

Step c.1) can be carried out both independently of step c) and in dependence on step c). It results z. B. that an extension of the hot gas generator, an increased amount of fuel is required for the same power. Likewise, a reduction in the amount of fuel at a shortening of the hot gas generator is usually appropriate. Also, this agent can be used in the stop positions of the hot gas generator for extended Ausreizen the process capabilities. Also, the type of fuel, i. H.

In particular, the composition of the fuel, be changed to a higher or lower proportion of high-calorie or low-calorie fuel. This can be achieved in particular a change in temperature, the amount of combustion gas and cost savings by increasing the lean gas content.

In a further advantageous embodiment of the method according to the invention, the combustion temperature for a process purpose is changed manually or automatically in a range from 200 ° C to 1,600 ° C.

• – beim Einsatz in Mühlen in einem Bereich von 200°C bis 300°C,
• – beim Einsatz bei der Kalkwäsche in einem Bereich von 400°C bis 800°C, und
• – beim Einsatz bei der Glasschmelze in einem Bereich von 1.300°C bis 1.600°C.

This temperature range from 200 ° C to 1,600 ° C is subdivided into the following temperature ranges, in particular for the following applications:

• When used in mills in a range of 200 ° C to 300 ° C,
• - when used in lime washing in a range of 400 ° C to 800 ° C, and
• - When used in the molten glass in a range of 1,300 ° C to 1,600 ° C.

Changing the combustion temperature may be achieved primarily by adjusting the type and / or amount of fuel, oxidizer, process gas, material flow, and / or cooling air. Indirectly, this is also possible with a constant or modified amount of fuel by the extension or shortening of the hot gas generator. Another possibility is in particular the change in the geometry of the burner device. The term "manual" not only means that the steps c) or c.1) are adjusted by the use of physical force, but primarily by human surveillance and manual entry of control variable changes takes place. By the term "automatic" is meant, in contrast, that the combustion temperature is changed as a result of a circuit.

In a further advantageous embodiment of the method according to the invention, an aggregate state of the material flow is determined and the combustion temperature is adjusted according to one of the preceding method steps. The term "state of aggregation" of the material flow means above all that the proportion of liquid constituents or the proportion of solids is registered. The state of aggregation can be detected with one of the aforementioned measuring means, but above all by a diversion of the material flow by means of a collecting container.

A further aspect of the invention relates to a hot gas generator for heating or drying a stream comprising a hot gas generator wall and at least one mixing chamber arranged therein for guiding and contacting a combustion gas flowing in the mixing chamber and a stream flowing through the mixing chamber, wherein the mixing chamber is variable in length.

Such a hot gas generator is particularly suitable or arranged for carrying out the method according to the invention. For this reason too, reference is made in addition to the explanations given there with regard to the arrangement of the components or their effects and configurations.

In particular, the hot gas generator wall is substantially (eg concentrically) arranged around the at least one mixing chamber and, for example, extends over the (maximum) length of the mixing chamber , Thus, the Heißgasgeneratorwandung is arranged in particular opposite to the burner device. The mixing chamber serves to guide and / or contact the combustion gas flowing in the mixing chamber (from the burner device) and the material flow flowing in from the outside of the mixing chamber. It is preferred here that only one (single) mixing chamber or chamber wall is provided, but this is not absolutely necessary. The guidance with the mixing chamber or chamber wall in particular has the consequence that the flow of material and / or combustion gas flows along the chamber wall and / or through the chamber wall. For this purpose, flow baffles (for example an end-side closure of the mixing chamber) and / or passages in the chamber wall can be provided. In addition, it should be achieved with the mixing chamber that intensive contacting, in particular a mixture, of a flow of material and combustion gas takes place.

For example, the mixing chamber may have a plurality of holes, slots, etc. in the chamber wall and is usually closed at the end. The mixing chamber of the hot gas generator may be designed with different shapes and / or cross sections, for. B. a round, oval, rectangular, polygonal cross-section. Furthermore, they may be straight or curved their longitudinal axis and be aligned in their spatial orientation primarily horizontal, but also perpendicular or at any other arbitrary angle. The chamber wall in particular has passages which are designed to discharge the combustion gas due to an increased internal pressure relative to the ambient pressure. Also for the shape of the holes, any geometrically conceivable shapes can be used and they can additionally have short tube pieces arranged at an angle to the chamber wall. Furthermore, the chamber wall is variable in length. The change in length of the mixing chamber can be achieved primarily by an external and controlled access. Here are z. B. pneumatic and gear rack combinations can be used. Furthermore, the hot gas generator can be guided by means of an elastic means in the shortest state to a stop and by increasing supply pressure from the combustion gas, the elastic means or the mixing chamber of the hot gas generator is lengthened. For this embodiment, the holes and the end of the closed mixing chamber are to be designed so that the necessary pressures can be generated.

In a further advantageous embodiment, the mixing chamber has a variable length and pressure compensation means are provided over the length, so that a constant pressure difference between an inner region and an outer region of the mixing chamber is adjustable. In other words, in particular, this means that a pressure difference between the flow of material and the combustion gas can be kept constant via suitably shaped and / or adaptable holes, slots, openings in the chamber wall via the mixing chamber. Hereby it can be achieved that the mixing processes and / or the gas exchange through the chamber wall (from inside to outside and / or vice versa) over the variable length are locally formed in each case approximately equally intense.

For example, if only equal sized and uniformly distributed holes over the length of the mixing chamber provided, the pressure drops due to the previously exiting combustion gas to the mixing chamber end out. According to the invention, this can be adapted to the above specification that the number and / or the shape and / or the cross section of the holes varies over the length, in particular increases and / or increases, starting from the burner device. Also in this embodiment, the holes may be formed in any geometric shape and may additionally have short, angled to the chamber wall, pipe sections.

• – eine Vorrichtung zum Bestimmen eines Wärmebedarfs,
• – eine Vorrichtung zum Bestimmen einer Menge an Stoffstrom,
• – eine Vorrichtung zum Bestimmen einer Qualität des Stoffstroms,
• – eine Vorrichtung zum Bestimmen einer Temperatur des Stoffstroms.

Also preferred is a hot gas generator in which at least one of the following devices is provided:

• A device for determining a heat demand,
• A device for determining an amount of material flow,
• A device for determining a quality of the material stream,
• - An apparatus for determining a temperature of the material flow.

In one embodiment of the hot gas generator, the latter has a device for determining a heat requirement. For example, a calorie meter is suitable for this purpose. In such a sensor can be registered by a low heat input via electrical heating either by increasing the power requirement at a constant temperature or at constant current, a reduction in the temperature of the respective elements. However, similarly acting measuring means can also be used. Also indirect measurement methods such. B. Temperature measurement in conjunction with a material flow meter can be used to determine the heat demand. The values can also be determined by calculation.

In a further embodiment, the hot gas generator has a device for determining an amount of a material flow. Suitable measuring means for detecting the amount of material flow are primarily fluidically acting sensors. For example, a speed can be determined via a propeller, which corresponds to an amount of a material flow. Furthermore, a Prandtl tube can be used, which can determine a speed from the pressure difference between back pressure and ambient pressure. When used in known cross sections through which the material stream flows, these measuring devices can be used to determine the quantity. Also, indirect determinations of the amount of a stream can be used, such. B. a flap position of a supply flap of the material flow, if the other flow values are known. Also, the measuring means can be used to determine the heat demand with simultaneous adjustment of the temperature, that is, a calorimeter or anemometer. Furthermore, the amount of a stream can be calculated.

According to another embodiment, the hot gas generator has a device for determining the quality of the material flow. Suitable measuring means for detecting the quality of the material stream are preferably optical sensors. Here, in particular, dust constituents can be detected in their quantity by changing the light transmittance. Alternatively or additionally, a heating element can be used which, similar to a calorimeter, allows conclusions as to the composition of the material flow due to current or temperature changes. Also, the quality can be determined based on calculations.

In a further advantageous embodiment of the hot gas generator, the latter has a device for determining a temperature of the material flow. Suitable measuring means for detecting the temperature of the stream can be any conventional measuring means, but for supplying as a control signal for adjusting the length of the hot gas burner, such a sensor is suitable for determining the temperature of the material flow, which is operated on the basis of electrical current or electrical voltage and thus outputs electrical signals. Here, especially thermocouples, infrared cells or UV cells and generally sensors based on the Seebeck or Peltier effect can be used. The location of the measurement of the temperature of the material stream can be arranged both before entering the mixing with combustion gases and after mixing with combustion gases. The measurement of the temperature of the stream before mixing with combustion gas can be useful, above all, if the stream still has an additional effect on the litigation, such. B. Cooling of mixing chambers of any kind. Furthermore, the temperature can be determined based on calculations.

According to a development, the hot gas generator has a control unit that is set up to carry out the method according to the invention. The method can be implemented as a data processing program that is implemented in the control unit. For this purpose, the control unit with the burner device, a drive for adjusting the length of the mixing chamber of the hot gas generator and / or at least one sensor directly or indirectly communicate and influence their operation or regulate. In addition, memory for measured values, characteristic values, limit values and / or method strategies can be provided there, which are taken into account when carrying out the method.

In an advantageous (and also independent from the previous aspects) embodiment, a hot gas generator for heating and / or drying of a stream is proposed, comprising a Heißgasgeneratorwandung and at least one mixing chamber arranged therein for guiding and contacting a combustion gas flowing in the mixing chamber and the mixing chamber having flow-inducing material flow, wherein the mixing chamber has at least one channel which is extend from outside to inside, in particular along a direction which is inclined to a diametrical direction.

Through the channel, the material flow is in particular bundled and thereby entered with an increased pulse in the flame or the combustion gas. This results in a better mixing and more efficient heating. In particular, a good adaptation to the respective quality of the material stream can be achieved by controlling the addition of the material stream, since the change in the pulse strength is amplified by the pressure gradient across the channel. The inclination of the channel additionally causes a spiral flow, which further supports the mixing. In this case, it is advantageous in particular that an efficient regulation of the output values can be achieved solely by controlling the material flow (eg pressure, volume flow) without having to change the burner device parameters. It is preferred, but combined in combination with a control of the flame.

In an advantageous development of this hot gas generator, a plurality of channels is provided, which are in particular at least partially differently inclined to the respective diametrical direction.

Due to the plurality of channels, the entry of the material flow is possible in a particularly uniform manner. In addition, a desired pressure gradient can be adjusted via the channels. In particular, the friction loss of the material flow over the number of channels can be reduced or increased. The angle of inclination can be adapted in particular to the position of the material flow inlet. In addition, the inclination can be adapted to a desired spiral flow or turbulent flow, with the particular efficient mixing can be achieved.

The invention finds particular application in a so-called hot gas burner for drying or heating a stream comprising a burner device and a hot gas generator, the hot gas generator being adapted to carry out the method steps as described above by means of a variable-length mixing chamber.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show particularly preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. Furthermore, the figures show flowcharts of the method steps, as they can be carried out in a technically meaningful way. Show it:

1 a variable-length mixing chamber of the hot gas generator with a heat demand measuring means;

2 : a variable-length mixing chamber of the hot gas generator with expanding holes and various measuring means;

3 a flow chart of the change in length of the hot gas generator based on a measured value;

4 FIG. 3 is a flow chart for changing the hot gas generator length and fuel quantity based on four results; FIG.

5 a hot gas generator with connection means; and

6 : A frontal view of a hot gas generator with channels in the manner of pipe sections.

1 shows a hot gas burner 17 comprising a burner device 9 and a hot gas generator 1 , The hot gas burner 17 gives through its hot gas generator wall 18 a room (outside area 22 ), because a material flow 10 is supplied. This one comes with the one inside 21 through holes 11 and slits 24 in the mixing chamber 2 of the hot gas generator 1 escaping combustion gas 5 brought into contact and mixed. The tangential and / or radial supply of the (cold) material flow 10 also leads to a cooling of the mixing chamber 2 , so that a low wear and a higher reliability can be realized here. In addition, such intimate contact with the mixing chamber 2 or the combustion gas located there 5 reached.

The burner device 9 becomes oxygen 7 , usually in the form of atmospheric oxygen, fed. Furthermore, alternately or simultaneously a high calorific fuel 6 and a weak gas 8th be supplied. The flame of combustion of the fuel gas mixture is usually only in the burner device 9 but can also get out of the burner device 9 in the mixing chamber 2 of the hot gas burner 1 protrude. But primarily, only the combustion gas flows 5 from the combustion in burner device 9 in the mixing chamber 2 of the hot gas generator 1 ,

The hot gas generator 1 consists of one in the end 3 closed mixing chamber 2 with a chamber wall 4 that have a lot of holes 11 over the entire length 20 the mixing chamber 2 having. Here are just parts of the holes 11 shown schematically. The distribution of the holes 11 may be due to the manufacturing process, the desired pressure distribution and / or to support a suitable mixing of the combustion gas 5 with the material flow 10 be executed. The same applies to the geometry of the individual holes 11 and / or slits 24 not necessarily over the entire length 20 the mixing chamber 2 of the hot gas generator 1 have to be the same.

Furthermore, purely schematically in representation and arrangement of a heat demand measuring means 12 shown. Also purely schematic is the Längenveränderlichkeit the hot gas generator 1 shown. These are mutually open pipe sections, each of which from left to right (in relation to the representation) are displaced or movable, and so the length 20 the mixing chamber 2 enlarge.

2 shows essentially all in 1 illustrated elements and relationships. This is additionally an actuating means 16 shown that - z. B. in the form of a rack or a pneumatic piston - for the change in length 20 the mixing chamber 2 of the hot gas generator 1 provides. It is irrelevant where this adjusting agent 16 is arranged. However, it results from the present temperatures that it makes sense technically, this adjusting agent 16 to be arranged at a suitable distance from the temperature peaks. For needs-based operation of these actuating means 16 is also a control unit 19 provided, the data is conductively connected in particular with at least one of the sensors that have been cited here.

Furthermore, in addition to the heat demand measuring means 12 another quantity measuring device 15 , a temperature measuring device 14 and an optical quality measuring device 13 shown. These are located in the inlet area of the material flow 10 , However, it may also be useful to have the measuring equipment so far from the hot gas generator 1 to space that a little to no heat or even little to no mixing with the combustion gas 5 is present. Likewise, it may also be desirable to record the values of the mixed combustion gases and material flows with some of the measuring devices mentioned.

In addition, there is also illustrated that the mixing chamber 2 a variable length 20 has and over the length 20 Pressure equalizing means 23 are provided, so that a constant pressure difference between an interior area 21 and an outdoor area 22 the mixing chamber 2 is adjustable. In the example shown, the pressure compensation means comprise 23 starting from the burner device 9 towards the opposite end of the mixing chamber 2 Growing holes 11 and / or slits 24 ,

3 shows a flowchart for carrying out a first variant of the inventive method, comprising the following steps: a) supplying and burning a fuel, b) determining a heat demand, and c) adjusting a length of the hot gas generator to the heat demand determined in step b). In 3 For example, the steps a) to c) are shown as being executed in alphabetical order depending on each other. It also illustrates that the method is executed in a loop.

4 shows a further embodiment of the method according to the invention. Here, in contrast to 3 to step a) four different measuring steps b) to b.3), which are first fed to a decision-making process or equalization process. Only then are the steps c) or c.1) carried out depending on the adjustment. The process is then looped back to step a).

5 shows a hot gas generator 1 on which the connection devices for the arrangement are shown in a process. The ignition device 26 is set up, the burner device 9 to start. About the combustion air intake 29 becomes the burner device 9 the oxidizer, ie air or oxygen supplied. About the fuel inlet 30 the respective fuel is added. Of course, a plurality of fuel inlets 30 and combustion air inlets 29 be provided. At the (eventually variable in length) burner nozzles 28 the mixture is incinerated or first mixed and burned there. The composition of the mixture, ie the volume flow or the ratio of individual volume flows, is determined by detecting the flame temperature via a radiation sensor 27 (eg, an ultraviolet sensor (UV sensor) or infrared sensor (IR sensor)). In the hot gas generator 1 becomes that of the burner device 9 generated a stream of material 10 via a material flow inlet 31 added. Herein is the material flow 10 dried and / or heated according to the method specified herein. Subsequently, the upgraded material flow flows 10 and the combustion gas through the connection opening 32 to a connected process.

In 6 becomes a hot gas dryer 1 in frontal view z. B. on the type of hot gas generator 1 shown. In this embodiment, the material flow 10 passing through the material flow inlet 31 is supplied via inclined to the respective diametrical direction channels 28 at the chamber wall 4 over the entire circumference of the mixing chamber 2 the flame passing through the six burner nozzles shown 28 is generated, added. As a result, good mixing and good surface volume ratio between flame or combustion gas and the material flow is achieved. It is clear that the channels can also be set up differently. It should be noted that this embodiment of the hot gas generator or the mixing chamber, regardless of the idea of the variable-length hot gas generator is a significant improvement over the prior art and therefore may be provided independently thereof.

Thus, the problems of the prior art are solved by the described method steps according to the invention and the hot gas generator according to the invention. It is thereby possible despite low volume of the hot gas burner, in particular by the short version, to allow the operation of such hot gas burner so that these effects of changing environmental conditions can be reduced or even avoided.

In particular, so the operation of a hot gas burner can be monitored in real time and regulated as needed. Thus, significantly better work results can be achieved, even if the environmental conditions change significantly. In particular, the quality, temperature and volume of the material stream can be controlled. In addition, the distribution of quality and temperature can be made uniform.

LIST OF REFERENCE NUMBERS

1

Hot gas generator

2

mixing chamber

3

The End

4

chamber wall

5

combustion gas

6

high calorific fuel

7

oxygen

8th

lean gas

9

burner means

10

material flow

11

hole

12

Heat demand measuring equipment

13

Quality measuring means

14

Temperature measurement means

15

Quantity measuring means

16

actuating means

17

Hot gas generator

18

Heißgasgeneratorwandung

19

control unit

20

length

21

interior

22

outdoors

23

Pressure equalizing means

24

slot

25

channel

26

ignition device

27

radiometer

28

burner

29

Combustion air inlet

30

fuel inlet

31

Material flow inlet

32

connection

Claims (11)

Method for drying and / or warming up a stream by means of a variable-length hot gas generator ( 1 ), which is flowed through by a stream, the method comprising at least the following steps: a) supplying and burning at least one fuel; b) determining a heat requirement for the treatment of the material stream; and c) adjusting a length of the hot gas generator ( 1 ) to the result from step b). Method according to claim 1, wherein before step c) an amount of the material flow is determined and in step c) adjusting the length of the hot gas generator ( 1 ) takes place to the specific amount of the material flow. Method according to one of the preceding claims, wherein before step c) a quality of the material flow is determined, and in step c) adjusting the length of the hot gas generator ( 1 ) to the specific quality of the material flow. Method according to one of the preceding claims, wherein before step c) a temperature of the material flow is determined and in step c) adjusting the length of the hot gas generator ( 1 ) takes place at the specific temperature of the material flow. Method according to one of the preceding claims, wherein depending on the result from step b) at least a quantity or a kind of the at least one fuel is adjusted. Method according to one of the preceding claims, wherein a combustion temperature for a process purpose manually or automatically in a range of 200 ° C to 1200 ° C can be changed. A method according to claim 6, wherein an aggregate state of the material flow is determined and the combustion temperature is adjusted according to one of the preceding method steps. Hot gas generator ( 1 ) for heating or drying a stream ( 10 ), comprising a Heißgasgeneratorwandung ( 18 ) and at least one mixing chamber ( 2 ) for guiding and contacting one in the mixing chamber ( 2 ) flowing combustion gas ( 5 ) and one the mixing chamber ( 2 ) streaming material ( 10 ), wherein the mixing chamber ( 2 ) is variable in length. Hot gas generator ( 1 ) according to claim 8, wherein the mixing chamber ( 2 ) a variable length ( 20 ) and over the length ( 20 ) Pressure compensation means ( 23 ) are provided, so that a constant pressure difference between an interior area ( 21 ) and an outdoor area ( 22 ) of the mixing chamber ( 2 ) is adjustable. Hot gas generator ( 1 ) according to one of the preceding claims 8 or 9, wherein the hot gas generator ( 1 ) comprises at least one of the following devices: - a device ( 12 ) for determining a heat requirement, - a device ( 15 ) for determining an amount of a material flow, - a device ( 13 ) for determining a quality of the material flow, - a device ( 14 ) for determining a temperature of the material stream. Hot gas generator ( 1 ) according to one of the preceding claims 8 to 10, wherein the hot gas generator ( 1 ) a control unit ( 19 ), which is adapted to carry out the method according to one of the claims 1 to 7.

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