DE102011082205A1 - Method for operating a regeneratively heated industrial furnace and regeneratively heated industrial furnace - Google Patents

Abstract

The invention relates to a method for operating a regeneratively heated by at least one regenerative heat storage (10) industrial furnace (100) having a furnace chamber (21) of a furnace (20), in particular with a melting tank for glass (20B), wherein the regenerative heat storage (10 ) has an oven-side heat storage gas passage (11, 11 ') to the furnace chamber (21) and an ambient heat storage gas passage (12) to the environment, comprising the steps: - secondary preheating the combustion air and supplying the secondary preheated combustion air (VL) to the regenerative heat storage (10) ; - Primary use of the exhaust gas in the regenerative heat storage (10) for the primary preheating of the combustion air (VL); - Secondary use (30) of the exhaust gas following the ambient heat storage gas passage (12) to the environment. According to the invention, it is provided that the secondary preheating of the combustion air (VL) from a waste heat of the furnace (20) is obtained, and in the operation of the industrial furnace (100) an exhaust gas outlet temperature at the ambient heat storage gas passage (12) is increased compared to an exhaust gas outlet temperature on ambient heat storage gas passage (12) without secondary preheating (40) of the combustion air (VL).

Description

The invention relates to a method according to the preamble of claim 1, for operating a regeneratively heated via at least one regenerative heat storage industrial furnace with a furnace chamber of a furnace, in particular with a melting tank for glass. The invention also relates to an industrial furnace according to the preamble of claim 11, with a furnace chamber, in particular with a melting tank for glass, which is regeneratively heated via at least one regenerative heat storage. The invention also relates to a use according to claim 17.

A regenerative industrial furnace of the type mentioned has proven particularly in glass production for melting glass. Basically, however, an industrial furnace of the type mentioned in the opening paragraph is not limited to use in glassmaking and can be used as an industrial high-temperature furnace, for example, in metal fabrication or the like.

Industrial furnaces that are heated with gas or oil or a mixture of these fuels are usually equipped with primary exhaust heat utilization by means of a regenerative heat storage, such as by means of a regenerator or recuperator or the like. This makes it possible to transfer a comparatively large proportion of the exhaust gas heat exiting from the furnace chamber of the furnace to the combustion air provided for entry into the furnace chamber. In this way, a fuel consumption can be reduced and at the same time comparatively high process temperatures in the furnace of up to 1650 ° C can be made possible. Although the actual temperatures are dependent on the size of a regenerator, recuperator or other regenerative heat storage on the furnace as well as the actual volumetric flows of the exhaust gas and the combustion air, the achievement of the highest possible preheat temperatures for the combustion air has usually priority, because this significantly fuel consumption and the achievable oven room temperatures determined. The primary use of the exhaust gas, ie the regenerative use of the amount of heat deposited by the exhaust gas in the regenerative heat accumulator, is the primary preheating of the combustion air in the foreground. For example, in EP 0 137 059 A1 a method for melting glass with a preheating of the batch to be abandoned on the glass bath and an energy supply to the furnace by means of gas or oil burner, wherein preheated by the exhaust gas combustion air is supplied. Part of the exhaust stream is used for final preheating of the supplied combustion air and the other part for batch preheating, wherein the exhaust gas streams are then recombined and make the initial preheating of the combustion air together.

Meanwhile, in an industrial furnace of the type mentioned in addition a secondary exhaust gas use - d. H. Waste heat utilization of the exhaust gas after its primary use in the regenerative heat storage for primary preheating of the combustion air - be provided to a residual residual temperature, i. to use the waste heat of the exhaust gas as an energy source. For this purpose, in addition to the primary use of the exhaust gas in the regenerative heat storage to primary preheating the combustion air and a secondary use of the exhaust gas is provided following the ambient heat storage gas passage to the environment.

For example, in US 4,528,012 a high-temperature industrial process for a glass melting furnace with two generators described. In this case, the exhaust gas is fed to a heat exchanger in which remaining residual heat of the exhaust gas is indirectly transferred to a compressed combustion air, which then expands in a high-performance turbine, wherein the turbine in turn drives a generator. This combustion air - secondary - preheated to 400 ° C to 450 ° C and then fed to the primary preheating by the exhaust gas a regenerator. Therefore, the regenerator stores a larger amount of heat, so that the exhaust gas outlet temperature is increased from the generator. The system produces secondary preheated combustion air and is also able to produce electricity via the turbine by means of the generator. This concrete method is relatively complicated and requires a considerable secondary preheating of the combustion air to a range of 400 ° C to 425 ° C. Nevertheless, a further increase in the combustion air preheating temperature by the secondary waste heat utilization of the exhaust gas can not be achieved or only very slightly.

The achievable Luftvorwärmtemperatur, ie achievable achievable by primary and secondary preheating of the combustion air temperature of the combustion air at the furnace heat storage gas passage (exhaust gas inlet and combustion air outlet) is limited by the temperature gradient between Abgaseintritt- and -austritt: As a result, the combustion air can not be hotter than that in the Regenerator on the furnace-side heat storage gas passage entering exhaust. In fact, the air preheating temperature always remains well below the exhaust gas temperature entering the regenerative heat storage. The closer the temperature of the preheated combustion air on the one hand and the incoming exhaust gas on the other come, the greater the effort to increase the combustion air preheating temperature.

The secondary waste heat utilization of the remaining residual heat of the exhaust gas, d. H. the secondary use of the exhaust gas following the ambient heat storage gas passage to the environment, thus becomes more important.

DE 10 2005 019 147 B4 describes, for example, a method for optimizing the combustion process for a melting furnace in the manufacture of glass, in which a regenerative heat exchanger consisting of firebricks is arranged on both sides of the glass tank. Such a structure allows flue gases from the melting process to be cooled down to approx. 520 ° C. To be able to use even more energy from the flue gases, they went to install behind the heat exchanger, a waste heat boiler for steam generation. The steam thus generated is then used, for example, in a condensing turbine for the production of electrical energy. The method described there seeks primarily to achieve a nearly constant temperature of the combustion air at the furnace-side heat storage gas passage.

It is desirable not only to preheat the combustion air effectively, but also to effectively utilize a waste heat of the exhaust gas secondarily.

At this point, the invention begins, the object of which is to provide a method and an industrial furnace in which, in addition to an effective combustion air preheating especially an effective secondary use of the exhaust gas is possible following the ambient heat storage passage to the environment. In particular, a device, a method and a use should be designed to make the secondary preheating of the combustion air as advantageous as possible. In particular, the secondary preheating of the combustion air should be designed advantageously with regard to a high-temperature industrial process. In particular, the method and the device should be designed with regard to a glass melting process. Advantageously, the secondary preheating of the combustion air should be made available under synergy effect with the glass melting process.

The object concerning the method is solved by a method of claim 1. In essence, the method provides for secondary preheating of the combustion air, primary use of the exhaust gas for primary preheating of the combustion air, and secondary use of the exhaust gas. According to the invention it is provided that the secondary preheating of the combustion air is obtained from a waste heat of the furnace. In the operation of the industrial furnace, an exhaust gas outlet temperature at the ambient heat storage gas passage is therefore increased compared to, for example, an exhaust gas outlet temperature at the ambient heat storage gas passage without secondary preheating of the combustion air.

The task concerning the industrial furnace is solved by an industrial furnace of claim 11. The industrial furnace has, in principle, a regenerative heat accumulator with an oven-side heat storage gas passage to the oven space and an ambient heat storage gas passage to the environment, wherein in the regenerative heat storage with primary use of the exhaust gas, a primary preheating of the combustion air can be implemented.

According to the invention it is provided that a waste heat treatment plant of the industrial furnace is designed to effect a secondary preheating of the combustion air. In addition, a supply is provided, by means of which the secondary preheated combustion air can be supplied to the regenerative heat storage.

An energy for secondary use of the exhaust gas following the ambient heat storage gas passage to the environment can in particular be such that during operation of the industrial furnace, an exhaust gas outlet temperature at the ambient heat storage gas passage is increased compared to an exhaust gas outlet temperature at the ambient heat storage gas passage without secondary preheating the combustion air.

The invention also leads to a use according to claim 17.

The invention is based on the consideration that the secondary waste heat utilization of the exhaust gas is all the more effective, the higher the remaining residual temperature of the exhaust gas after the regenerative heat storage, ie after a regenerator or recuperator. The concept of the invention has recognized that, above all, a significantly improved efficiency of a downstream secondary utilization process of the exhaust gas waste heat can be achieved if the secondary preheating of the combustion air is designed effectively. In addition, the concept of the invention has recognized that at the industrial furnace waste heat is available, which - directly - is hardly usable; This is due to the relatively low temperatures of the waste heat of the furnace. However, the directly barely usable waste heat can be used after the realization of the invention, however, to make the secondary preheating of the combustion air particularly effective. The concept of the invention has namely recognized that - even at comparatively low temperatures of low-value and directly hardly usable waste heat of the furnace - this still can be transmitted to a much higher temperature level via a so far "externally" preheated combustion air from comparatively low temperature level. This results in the secondary use of the exhaust gas following the ambient heat storage gas passage to the environment to a much improved efficiency; for example, to a much improved effectiveness of steam and electric power generation. As a result, a higher residual heat is obtained in the exhaust gas for secondary use, which is much more effective for the secondary utilization process. In other words, the method increases the efficiency of a secondary use of waste heat after the regenerative heat storage, for example a regenerator or recuperator, of an industrial furnace by supplying preheated air to the heat storage for heating; this with the aim of reducing the cooling of the exhaust gas at the outlet of the heat accumulator and provide the secondary waste heat recovery in this way a higher usable exhaust heat available.

This is done without any reduction or even slight increase in the priority primary combustion air preheat temperature in the range of 1,000 to 1,200 ° C. Ie. In contrast to the prior art, no losses are made in the conventional furnace process and yet the secondary use of the exhaust gas is substantially improved.

As a result, the concept of the invention achieves effective secondary preheating of the combustion air by the skillful use of waste heat from the furnace. Thus, not only the otherwise rarely used waste heat of the furnace is utilized, but it is also achieved for the secondary exhaust utilization process, a higher efficiency. Thus, the concept of the invention not only synergistically uses waste heat processes of the furnace, but also focuses on the secondary use of the exhaust gas and secondary preheating of the combustion air. This is less the primary combustion air preheating in the foreground, since these - as recognized by the invention - anyway subject to a limited efficiency.

Under secondary use of the exhaust gas is basically any use of a heat content of the exhaust gas at the connection to the ambient heat storage gas passage, so the residual heat of the exhaust gas to understand. In particular, in a first mode of use, a secondary use may be the conversion of the residual heat to another form of energy, e.g. electrical energy, concern. In a second type of use, a secondary use in the form of recycling the waste heat into the process of glass melting has proven to be particularly advantageous. It has been shown that the glass melting process, especially in the field of preheating, offers good feed-in possibilities even for heat quantities at a comparatively low temperature potential. This also improves the efficiency of a secondary exhaust gas use in the overall process, since the residual heat of the exhaust gas is advantageously reused within the melting process, in particular without being converted and / or leaving the melting process. In particular, the use of residual heat has proven to preheat a glass batch or to preheat shards.

Under waste heat of a furnace is basically any waste heat to understand that is the environment of the furnace removed or the furnace chamber itself can be removed, but not the heat content of the exhaust gas. In this respect, a difference is made here between waste heat of the furnace and heat content, in particular residual heat, of the exhaust gas.

The concept of the invention also leads to a preferred heat exchange process in the regenerative heat storage. In particular, it is provided that the primary use of the exhaust gas in the regenerative heat storage for primary preheating of the combustion air while lowering the exhaust gas temperature from an exhaust gas inlet temperature on furnace-side heat storage gas passage (exhaust gas inlet) to an exhaust gas outlet temperature at the ambient heat storage gas passage (exhaust gas outlet). In the regenerative countermove (in the regenerator periodically thereafter, in the recuperator at the same time), this takes place while raising the combustion air temperature from a combustion air initial temperature at the ambient heat storage gas passage (combustion air inlet and exhaust outlet) to a combustion air outlet temperature at the furnace-side heat storage gas passage (combustion air outlet and exhaust gas inlet).

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the task and with regard to further advantages.

Preferably, secondary preheated combustion air is not recovered as fresh air and heated from an initial temperature to a preheating temperature. An initial temperature may be, for example, between 10 ° C and up to 60 ° C; usual way z. B. at an ambient temperature in the range between 15 ° C and 30 ° C. Advantageous the secondary preheated combustion air will have a preheating temperature above the initial temperature and up to 250 ° C. Depending on the available waste heat of the furnace, the secondary preheated combustion air can thus be raised to a suitably much higher temperature level. Nevertheless, the temperature level of the secondary preheated combustion air according to this development is well below a corresponding in the prior art, for. In US 4,528,012 , proposed temperature level. On the one hand, this is based on the concept of the present development, to use waste heat of the furnace, so that so compared to known measures simplified secondary preheating process for combustion air is achieved, which also synergistically uses the waste heat of the furnace. On the other hand, the process is mainly designed to use a lower temperature level of up to 250 ° C, optionally up to 300 ° C or 350 ° C, depending on the waste heat of the furnace.

Nevertheless, in a particularly preferred manner, an exhaust gas outlet temperature at the ambient heat storage gas passage is significantly increased compared to an exhaust gas outlet temperature at the ambient heat storage gas passage without secondary preheating of the combustion air. Preferably, an exhaust gas outlet temperature at the ambient heat storage gas passage is increased by up to 150 ° C. Advantageously, the exhaust gas outlet temperature is in the range between 400 ° C to 800 ° C. Basically, the development has recognized that even comparatively small increases in the exhaust gas outlet temperature at the ambient heat storage gas passage are suitable in order to substantially improve a secondary process in terms of its efficiency.

In a particularly preferred further developing first variant, it is provided that for secondary preheating of the combustion air from a waste heat of the furnace, waste heat-carrying furnace air is sucked out of the furnace chamber and with this not secondarily preheated combustion air, d. H. especially fresh air, secondarily preheated. An industrial furnace preferably has a waste heat treatment plant in the form of a suction connected to the furnace chamber for exhaust air bearing furnace air. In a preferred embodiment of this measure, it is provided that a melting tank for glass is arranged in the furnace chamber of the furnace and is sucked for secondary preheating of the combustion air from waste heat of the furnace, waste heat-carrying air from a slosh edge of the melting tank. As a result, on the one hand, a cooling of the slosh edge is achieved, which inhibits corrosion processes at the slosh edge or significantly reduced. On the other hand, the waste heat of the furnace thus obtained is used in an improved efficiency for secondary preheating the combustion air in order to increase the efficiency of the secondary exhaust gas utilization in particular. This synergistic effect of the first variant is equally advantageous for the glass melting process as well as the secondary use of exhaust gas.

Usually, waste heat is achieved at an outdoor area of a furnace by the blowing of cooling air, which is then discharged into the environment unused. In a preferred second further development variant, it is provided that, for secondary preheating of the combustion air from waste heat of the furnace, ambient air carrying waste heat, in particular cooling air, is obtained by cooling at an outer region of the furnace. Preferably cooling air is obtained at an outside area of particularly elevated, in particular largest, outside temperature heat-carrying cooling air by cooling at an outside area of the furnace or other ambient air. In a particularly preferred manner, inflowing fresh air can be sucked in, in particular freely or guided (for example via a ventilator or other positively-driven or naturally-circulated functionality), and conducted over the outside area of the furnace. For this purpose, an industrial furnace preferably has a waste heat treatment plant in the form of an extraction of fresh air connected to an oven outer area, in order to provide cooling air carrying waste heat. Thus, the integrity of the furnace can be maintained as such and at the same time provide the waste heat obtained from the secondary preheating of the combustion air available; this in turn to achieve an efficiency-enhanced secondary exhaust gas utilization.

In the context of a particularly preferred development, it is provided that an exhaust gas outlet temperature at the ambient heat storage gas passage is regulated by means of the secondarily preheated combustion air as the manipulated variable, in particular from an actual value to a desired value. It has been found that the heating period-averaged exhaust gas exit temperature, ie, the exhaust gas temperature averaged over a firing period, may undergo relatively large process-dependent fluctuations from period to period. The proposed according to this development control concept uses in a preferred manner, the formation of secondary preheated combustion air to correct the fluctuations. Preferably, the heating period-averaged target value is a constant value, ie the aim of the control is to keep the averaged over a period exhaust gas temperature from period to period substantially constant or at least in a certain range. This leads advantageously to the fact that at least over a day or the like period averaged exhaust gas temperature - otherwise unchanged process - is largely constant.

A preferred embodiment of the industrial furnace provides a control device which is designed to carry out the further processing steps. In particular, a control device has proved to be advantageous, which is a module with a predictive control based on a mathematical model of heat transfer and heat storage in the regenerative heat storage is formed. Since the heat transfer and storage process in the regenerative heat storage is a comparatively slow process, the predictive control according to the development is particularly suitable. Obtaining a largely reliable, in particular constant, exhaust gas outlet temperature at the ambient heat storage gas passage can be advantageously carried out in order to support the reliability of the secondary exhaust gas utilization.

Embodiments of the invention will now be described below with reference to the drawing in comparison with the prior art, which is also partly shown.

This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The features disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article that would be limited in comparison to the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and arbitrarily usable and claimable. Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

1 a schematic representation of a preferred embodiment of a method for operating a at least one regenerative heat storage regeneratively heated industrial furnace with a furnace chamber of a furnace having a melting tank for glass;

2 a schematic representation of an industrial furnace with two regenerators, which are operated alternately, a furnace and a secondary exhaust gas use and a secondary preheating of the combustion air - different waste heat sources of the furnace are shown schematically.

1 schematically and generally illustrates a method of operating a via at least one regenerative heat storage 10 regeneratively heated industrial furnace 100 with a stove room 21 for the oven 20 , The regenerative heat storage 10 in the present case has an oven-side heat storage gas passage 11 to the oven room 21 of the oven 20 and an ambient side heat storage gas passage 12 to the environment. In regenerative heat storage 10 , which in the present case may be a regenerator or recuperator, the primary use of an exhaust gas AG for the primary preheating of combustion air VL takes place. In the case of a regenerator, this is sequentially loaded once with exhaust gas AG and once with combustion air VL, ie flows through time one after another in predetermined periods in the reverse direction once with exhaust gas AG and once with combustion air VL. In the case of a recuperator this is flowed through with exhaust gas AG and combustion air VL in the constant heat exchange.

In regenerative heat storage 10 the exhaust gas AG is a part of its heat energy to the combustion air VL under preheating of the same. Specifically, a lowering of the exhaust gas temperature T _AG from an exhaust gas inlet temperature T _AG-in ^{1 takes place} at the furnace-side heat storage gas passage 11 (Exhaust gas inlet) to an exhaust gas exit temperature T _AG-in ² at the first ambient side heat storage gas passage 12 (Gas outlet). Due to the illustrated with dotted arrow primary heat exchange WA between exhaust AG and combustion air VL is an increase in the combustion air temperature, namely the increase of a combustion air inlet temperature T _{VL in} ¹ at the second ambient heat storage gas passage (combustion air inlet) to a combustion air outlet temperature T _VL-out ¹ at the furnace heat storage gas passage 11 (Combustion air outlet and exhaust gas inlet).

In the present case, exhaust gases AG could burn out of the furnace room 21 with about T _AG-in ¹ in the range of 1400 ° C to 1550 ° C in the regenerative heat storage 10 enter and leave this with a residual temperature T _AG-in ² of about 400 ° C to 600 ° C. In systems of the prior art, exhaust gases of this temperature are optionally discharged into a chimney, so that the heat contained at the residual temperature of 400 ° C to 600 ° C remains unused. Also, the combustion air in systems of the prior art with an initial temperature of the environment of about 30 ° C to 60 ° C (T _VL-in ¹ ) enter directly into the regenerative heat storage and after the primary preheating of the regenerative heat storage with a preheating temperature T. _VL-out ¹ from about 1000 ° C to 1200 ° C in the furnace chamber 21 enter.

In the present embodiment embodying the concept of the invention, secondary use of the exhaust gas AG is subsequent to the ambient heat storage gas passage 12 intended for the environment. The secondary use 30 the exhaust gas sees a steam generator 31 and a steam generator 31 downstream steam turbine 32 in front. To the steam turbine 32 is a generator 33 connected, which serves to generate electricity. Basically, the secondary use of the exhaust gas 30 can also be realized in other ways, so that the present embodiment, inter alia, with regard to the secondary use of the exhaust gas 30 can be modified. For example, the exhaust gas AG can also be placed directly on an exhaust gas turbine and drive a generator under expansion.

The present embodiment sees, in contrast to the prior art, a secondary preheating 40 the combustion air VL before. The combustion air passes as fresh air with an initial temperature T _VL-in ² between about 15 ° C and 70 ° C in the secondary preheating 40 one. The secondary preheated combustion air - whose temperature is thus raised by a temperature amount of .DELTA.T _VL - is the regenerative heat storage 10 fed. Ie. the supply temperature of the combustion air is T _VL-in ¹ = T _VL-in + ΔT _VL . On the one hand, this can be the outlet temperature of the combustion air T _VL-out ¹ at the output of the heat accumulator 10 increase; in any case, for example, to an air preheating temperature T _VL-out ¹ in the range of about 1000 ° C to 1200 ° C. According to the concept of the invention, above all a higher usable exhaust gas heat of the exhaust gas, namely T _AG-in ² = T _AG-out + ΔT _{AG is} provided. Since the cooling of the exhaust gas AG is slowed down, the residual temperature of the exhaust gas increases significantly; in this case, for example, ΔT _AG = 50 ° C.

For example, for a regenerative heat use in a glass melting process, an implementation can be carried out as follows. A combustion air is at normal ambient temperature as fresh air with an initial temperature T _VL-in ² in the range between 30 ° C to 60 ° C of the secondary combustion air preheating 40 supplied and heated to a temperature of T _VL-in ¹ of, for example 150 ° C and at this temperature T _VL-in ¹ in the regenerative heat storage 10 (ie T _VL-in ¹ = T _VL-in ² + ΔT _VL where ΔT _VL = 120 ° C-90 ° C). Although the combustion air preheating increases with furnace-side heat storage gas passage 11 in the oven room 21 only insignificant; in the example by about 10 ° C to 20 ° C. However, the cooling of the exhaust gas AG is decelerated as explained, so that the residual temperature of the exhaust gas increases by about ΔT _AG = 50 ° C.

The concept of the invention is thus low-value and directly hardly usable heat .DELTA.T _VL in the range between 120 ° C and 90 ° C from a waste heat 50 won the furnace and to raise the exhaust gas temperature at the entrance to the secondary exhaust gas use 30 used to a much higher temperature level; this will increase the effectiveness of secondary exhaust gas utilization 30 significantly improved.

The waste heat 50 of the furnace is present with a first variant of an exhaust gas heat treatment plant 51 and a second variant of an exhaust gas heat treatment system 52 shown. The first variant of an exhaust heat treatment plant uses waste heat from the interior of the furnace, ie waste heat from the furnace chamber 21 , The second exhaust heat treatment plant uses waste heat from a furnace outer area 22 , The waste heat 50 can be introduced, for example by a waste heat exchange AWA1, AWA2 for secondary preheating the combustion air VL in the combustion air VL. Basically, in the illustrated embodiment, a heat exchange WA or AWA1, ABA2 occur directly, ie using the same flow paths of combustion air as a heat receiver and heat supplier (in WA, the exhaust gas AG and AWA1, AWA2 the waste heat 51 . 52 ). The heat exchange WA, AWA1, AWA2 can also be done indirectly using suitable heat exchanger units or the like.

A concrete example for carrying out the method is in 2 explained on an industrial furnace for glass melting. 2 shows a simplified representation of a regeneratively heated industrial furnace 100 in which like reference numerals are used to simplify the same or similar parts or parts of the same or similar function.

The industrial furnace 100 has a furnace room 21 with an upper oven 20A and a glass melting tank 20B on. In the glass melting tank containing glass G is placed over the oven room 21 heated above the melting temperature and for the production of Flat glass or the like melted and treated appropriately. The industrial furnace 100 is heated in the present case, by a plurality of laterally mounted fuel injectors 23 Fuel - in the form of fuel gas - in the upper furnace 20A is injected. From fuel injectors 23 In the present case, a right-hand fuel injector is represented symbolically. Fuel injectors 23 are (although not shown in detail) both on the left and on the right side of the oven room 21 arranged, for example, opposite each other; For example, on each side of the oven room 21 three, four, five, six or more fuel injectors 23 be arranged.

In a firing period is via a fuel injector 23 Fuel gas in the upper furnace 20A injected virtually without combustion air. Above the fuel injector 23 is preheated - here primary and secondary preheated - combustion air VL through a left left furnace heat storage gas passage shown 11 the upper furnace 20A fed. The combustion air VL from the furnace-side heat storage gas passage 11 mixes in the upper furnace 20A with the fuel injector 23 injected fuel gas and leads to the formation of a sub-furnace with melting tank 20B covering flame. 2 shows the industrial furnace 100 in the state of a regenerative firing on the left, formed as a regenerator, heat storage 10 and the left injectors 23 , The injectors 23 and the furnace-side heat storage gas passage 11 are designed such that via the injectors 23 supplied fuel gas in a sufficient near or substoichiometric range with combustion air VL of the left regenerator in the upper furnace 20A is mixed. The in 2 illustrated operating state of a left-side firing of the upper furnace 20A under injection of fuel gas via the left injectors 23 and the supply of combustion air VL via the left regenerator lasts for a first period, which may, for example, be in the range of 20 to 40 minutes. During this first period, combustion air VL becomes the upper furnace 20A in the oven room 21 supplied separately from the fuel gas. During the first period exhaust gas AG is from the upper furnace 20A via a right oven-side heat storage gas passage 11 ' fed to the right regenerator, not shown, and heats it up.

In a second operating state, the firing of the upper furnace is for a second period of similar length of time 20A vice versa. For this purpose, then combustion air VL via a right regenerator, not shown, the upper furnace 20A along with fuel gas from the right injectors 23 supplied; the combustion air VL then absorbs the heat deposited by the exhaust gas AG in the first period in the right regenerator. Furthermore, exhaust gas AG during the second period in the left regenerative heat storage 10 introduced and heats up this. This allows the in 1 already described heat exchange WA for primary preheating the combustion air VL with heat of the exhaust gas AG.

The regulation of a fuel flow and / or a combustion air flow takes place basically via a not shown in detail temperature control module of a symbolically shown control 200 , In principle, a PID controller in the temperature control module can be used in accordance with which, increasing the fuel flow and / or the combustion air flow, a furnace chamber temperature is increased or a furnace chamber temperature is lowered while lowering a fuel flow and / or a combustion air flow. To do this, the controller 200 Temperature values of the regenerator head and / or the upper furnace space 20A fed. Corresponding temperature value lines 201 . 202 and temperature probes T1, T2 are in 2 shown. In the present case, the temperature probes T1, T2 can also be combined with a suitable lambda probe for measuring a fuel air ratio in order to set it in the same manner.

In the present case of an industrial furnace 100 is - the scheme of the concept of the invention, as described by 1 generally explained, following - a secondary preheating 40 the combustion air VL provided. The combustion air VL is considered fresh air FL with an initial temperature, approximately in the range between 30 ° C to 60 ° C, the secondary preheating 40 the combustion air supplied (T _VL-in ² ). The combustion air VL leaves the secondary preheating 40 with an increased temperature of T _VL-in + ΔT _VL across the feed 43 , About the feeder 43 the secondary preheated combustion air VL is the regenerator 10 fed and via the heat exchange WA this takes on the cached waste heat of the exhaust gas AG in the context of the primary preheating the combustion air VL.

To a secondary preheating 40 the combustion air to operate VL is the industrial furnace 100 a waste heat treatment plant 51 . 52 for waste heat 50 of the oven 20 intended. This serves for the recovery of waste heat (here from furnace air 51.1 ) from the oven room 21 and / or for recovering waste heat from an exterior of the furnace 20 , in this case a cooling air 52.1 at the oven outside area 20C ,

In a first variant sees the waste heat treatment plant 51 one to the upper furnace room 20A and the sub-furnace chamber connected suction for waste heat-carrying furnace air before; namely by suction of waste heat bearing furnace air 51.1 from a slosh of the melting furnace 20B , The intake of furnace air 51.1 from a slosh edge also actively serves to corrosion processes at the melting tank 20B to reduce. The waste heat 50 the waste heat treatment plant 51 According to the first variant can suitably via a waste heat pipe 51.2 the secondary preheating 40 be supplied.

A second waste heat treatment plant 52 for the recovery of waste heat 50 is in the form of an oven outside area 20C connected intake of fresh air FL formed to a waste heat-carrying cooling air 52.1 to provide. The cooling is in the present case a suction cooling, in the present case freely incoming fresh air FL is sucked in and over the outside of the furnace 20 is directed. The suction has proved to be advantageous in order to make the waste heat-carrying cooling air available for the further process. The waste heat carrying cooling air 52.1 can be via a suitable waste heat pipe 52.2 the secondary preheating 40 be provided for combustion air VL.

In the present case, an exhaust gas outlet temperature can pass through the ambient heat storage gas 12 due to the secondary preheated combustion air VL be increased by up to 150 ° C, ie in the range of 400 to 800 ° C; This is because the cooling of the exhaust gas AG is slowed as a result of reduced at elevated combustion air temperature heat exchange WA.

In addition, the controller indicates 200 in the present case a control module 210 on, which is a AbgasIstwert temperature T _AG ^is a temperature probe T2 at the ambient heat storage gas passage 12 receives and an exhaust gas setpoint temperature T _AG ^{should be} as a rule. The setpoint temperature T _AG ^will present case is a constant value as a substantially constant exhaust gas temperature for energy to secondary use 30 of the exhaust gas AG should be made available. According to the deviation between the setpoint temperature T _AG ^will and actual temperature T _AG ^Is are the throttles 41 . 42 the waste heat pipes 51.3 . 52.2 set to set a suitable secondary combustion air preheating, ie to set a suitable increase ΔT _{VL of} the combustion air temperature in the secondary preheating. The control device 200 has a module 210 with a predictive scheme based on a mathematical model of heat transfer and heat storage WA in regenerative heat storage 10 the actual value temperature is regulated to setpoint temperature.

LIST OF REFERENCE NUMBERS

10

 heat storage

11, 11 '

 furnace-side heat storage gas passage

12

 ambient heat storage gas passage

20

 oven

20A

 top furnace

20B

 Glass melting tank

20C

 Stove Outside

21

 furnace

22

 Stove Outside

23

 fuel injectors

30

 secondary use

31

 steam generator

32

 steam turbine

33

 generator

40

 secondary preheating

41, 42

 throttle

43

 feed

50

 waste heat

51

 first variant of a waste heat treatment plant

51.1

 furnace air

51.2, 52.2

 heat conduction

52

 second variant of a waste heat treatment plant

52.1

 cooling air

100

 industrial furnace

200

 control

201, 202

 Temperature value lines

210

 control module

AG

 exhaust

FL

 fresh air

G

 Glass

T _AG

 exhaust gas temperature

T _VL-in ¹ , T _VL-in ²

Combustion air inlet temperature

T _VL-out ¹

 Combustion air outlet temperature

T _AG-in ¹ , T _AG-in ²

 Exhaust gas inlet temperature

ΔT _VL

 increase

ΔT _AG

 increase

T _AG-out

 Exhaust gas outlet temperature

T1, T2

 temperature probes

T _AG ^is

 Exhaust gas temperature actual value

T _AG ^should

 Exhaust setpoint temperature

VL

 combustion air

WA, AWA1, AWA2

 heat exchange

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0137059 A1 [0003]
• US 4528012 [0005, 0023]
• DE 102005019147 B4 [0008]

Claims (17)

Method for operating a via at least one regenerative heat storage ( 10 ) regeneratively heated industrial furnace ( 100 ) with a furnace space ( 21 ) of a furnace ( 20 ), in particular with a melting tank for glass ( 20B ), wherein the regenerative heat storage ( 10 ) an oven-side heat storage gas passage ( 11 . 11 ' ) to the oven room ( 21 ) and an ambient side heat storage gas passage ( 12 ) to the environment, comprising the steps: - secondary preheating of the combustion air and supply of the secondary preheated combustion air (VL) to the regenerative heat storage ( 10 ); Primary use of the exhaust gas in the regenerative heat storage ( 10 ) for the primary preheating of the combustion air (VL); - secondary use ( 30 ) of the exhaust gas following the ambient heat storage gas passage ( 12 ) to the environment; characterized in that the secondary preheating of the combustion air (VL) from a waste heat of the furnace ( 20 ) and in the operation of the industrial furnace ( 100 ) an exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) is increased relative to an exhaust gas exit temperature at the ambient heat storage gas passage ( 12 ) without secondary preheating ( 40 ) of the combustion air (VL). A method according to claim 1, characterized in that the non-secondarily preheated combustion air (VL) is obtained as fresh air (FL) and is heated from an initial temperature to a preheating temperature. A method according to claim 1 or 2, characterized in that a non-secondary preheated combustion air (VL), in particular fresh air (FL), an initial temperature between 10 ° C and up to 60 ° C. Method according to one of claims 1 to 3, characterized in that a secondary preheated combustion air (VL) has a preheating temperature above an initial temperature, and the preheating temperature up to 250 ° C, preferably up to 350 ° C, is. Method according to one of claims 1 to 4, characterized in that the exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) is increased by up to 150 ° C, in particular in the range of 400 ° C to 800 ° C. Method according to one of claims 1 to 5, characterized in that for secondary preheating ( 40 ) of the combustion air (VL) from a waste heat of the furnace ( 10 ), Waste heat-carrying furnace air ( 51.1 ) from the oven room ( 21 ) is sucked and with this not secondarily preheated combustion air (VL), in particular fresh air (FL), is preheated secondarily. Process according to claim 6, characterized in that in the furnace chamber ( 21 ) of a furnace ( 10 ) a melting tank for glass ( 20B ) and for secondary preheating ( 40 ) of the combustion air (VL) from a waste heat of the furnace ( 10 ) Waste heat bearing furnace air ( 51.1 ) from a sloshing edge of the melting tank ( 20B ) is sucked. Method according to one of claims 1 to 7, characterized in that for secondary preheating ( 40 ) of the combustion air (VL) from a waste heat of the furnace ( 10 ), Waste heat-carrying ambient air, in particular cooling air ( 52.1 ) by cooling on an outside area of the furnace ( 20C ), especially at an outdoor area of greatest external temperature. A method according to claim 8, characterized in that the cooling is a suction cooling, in particular ambient air or incoming fresh air (FL) is sucked in and over the outer area of the furnace ( 20C ). Method according to one of claims 1 to 9, characterized in that by means of secondary preheated combustion air (VL) as a manipulated variable, an exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) is controlled by an actual value to a desired value, in particular the desired value is a heating period-averaged constant value. Industrial furnace with a furnace room ( 21 ), in particular with a melting tank for glass ( 20B ), which via at least one regenerative heat storage ( 10 ) is regeneratively heated, wherein the regenerative heat storage ( 10 ) an oven-side heat storage gas passage ( 11 . 11 ' ) to the oven room ( 21 ) and one ambient heat storage gas passage ( 12 ) to the environment, wherein in the regenerative heat storage ( 10 ) is a primary preheating of the combustion air (VL) can be implemented with primary use of the exhaust gas, further comprising: - a waste heat treatment plant of the industrial furnace ( 20 ), in particular the furnace space ( 21 ), which is adapted to a secondary preheating ( 40 ) of combustion air (VL); - a feeder ( 41 ) by means of the secondary preheated combustion air (VL) to regenerative heat storage ( 10 ) can be supplied; - an energy production for secondary use ( 30 ) of the exhaust gas following the ambient heat storage gas passage ( 12 ) to the environment, whereby - during operation of the industrial furnace ( 100 ) an exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) can be increased with respect to an exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) without secondary preheating ( 40 ) of the combustion air (VL). Industrial furnace ( 20 ) according to claim 11, characterized in that the regenerative heat storage 10 ) is a regenerator or a recuperator which passes through an oven-side heat storage gas ( 11 . 11 ' ) as exhaust gas inlet and combustion gas outlet to the furnace chamber ( 21 ), and having an ambient side heat storage gas passage as combustion air inlet and exhaust outlet to the environment. Industrial furnace ( 20 ) according to claim 11 or 12, characterized in that the waste heat treatment plant in the form of a furnace chamber ( 21 ) connected suction for waste heat bearing furnace air ( 51.1 ) is formed. Industrial furnace ( 20 ) according to any one of claims 11 to 13, characterized in that the waste heat treatment plant in the form of a at a furnace outer area ( 20C ) intake of fresh air (FL) is connected to a waste heat-carrying cooling air ( 52.1 ) to provide. Industrial furnace ( 20 ) according to one of claims 11 to 14 characterized by a control device for carrying out a method according to one of the preceding claims. Industrial furnace ( 20 ) according to claim 15, characterized in that the control device comprises a module with a predictive control based on a mathematical model of heat transfer and heat storage in the regenerative heat storage. Use of a secondary preheating of the combustion air and supply of the secondary preheated combustion air (VL) to a regenerative heat storage ( 10 ), wherein the secondary preheating of the combustion air (VL) from a waste heat of the furnace ( 20 ) is won; For the operation of a via the at least one regenerative heat storage ( 10 ) regeneratively heated industrial furnace ( 100 ) with a furnace space ( 21 ) of a furnace ( 20 ), in particular with a melting tank for glass ( 20B ), wherein the regenerative heat storage ( 10 ) an oven-side heat storage gas passage ( 11 . 11 ' ) to the oven room ( 21 ) and an ambient side heat storage gas passage ( 12 ) to the environment; and wherein during operation: - a primary use of the exhaust gas in the regenerative heat storage ( 10 ) for the primary preheating of the combustion air (VL), and - a secondary use ( 30 ) of the exhaust gas following the ambient heat storage gas passage ( 12 ) to the environment takes place; and wherein - during operation of the industrial furnace ( 100 ) an exhaust gas outlet temperature at the ambient heat storage gas passage ( 12 ) is increased relative to an exhaust gas exit temperature at the ambient heat storage gas passage ( 12 ) without secondary preheating ( 40 ) of the combustion air (VL).

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