METHOD AND APPARATUS FOR AUTOMATIC REMOVAL OF CARBON DEPOSITS FROM THE OVEN CHAMBERS AND FLOW CHANNELS OF NON-RECOVERY AND HEAT-RECOVERY COKE OVENS

Abstract

A method for the automatic removal of carbon deposits from the oven chambers and flow channels of non-recovery and heat-recovery coke ovens, where a coke oven battery, composed typically of a plurality of adjacently arrayed coke oven chambers, is utilized for the cyclical coking of coal, and where an air metering device which operates with superatmospheric pressure is used in order to remove, by combustion, carbon deposits in the flow cross-sections of the oven system and thereby to counteract a reduction in oven performance. An apparatus with which this method can be performed is also disclosed, this apparatus being integrated into the coke oven battery and at least one coke oven chamber wall, allowing the carbon deposits to be removed during operation without a change in any arrangement.

Description

The invention relates to a method for automatic removal of carbon deposits from flow channels in “Non-Recovery” and “Heat-Recovery” coke ovens, there being utilized one coke oven bank typically comprised of several coke oven chambers arranged side by side for cyclical carbonization of coal, and there being used an air dosage facility operating at positive pressure in order to remove carbon deposits accumulating in flow cross-sections of the oven system by combustion and thereby counteracting a reduction of the oven performance rate. The invention also relates to a device by means of which this method can be implemented, wherein this device is integrated into the coke oven bank and at least into one coke oven chamber, so that carbon deposits can be removed during operation without modifying any arrangement.

Carbonization of coal to obtain coke is often accomplished in coke oven chambers of the so-called “Non-Recovery” or “Heat Recovery” type which are distinguished from conventional coke oven chambers in that the coke oven gas evolving during coal carbonization is not captured and recovered but utilized for combustion and heating. On coal carbonization in this oven type, the gas evolving during coal carbonization streams into a gas space located above the coke cake where partial combustion of the coke oven gas occurs with a sub-stoichiometric quantity of air. As a result hereof, the coal or coke cake is heated from above. The gas space above the coke cake is also called primary heating space.

Partly burnt coking gas from the primary heating space is then passed via so-called “downcomer” channels into flue gas channels located under the coke oven chamber bottom floor and provided for complete combustion of partially burnt coke oven gas. These are supplied with secondary combustion air through secondary air soles connected to the atmosphere outside. The gas space under the coke cake is also called secondary heating space. In the majority of layouts, the vertically arranged downcomer channels pointing downwards in the direction of flow are located in non-frontal side walls of the coke oven chambers whereby partially burnt coke oven gas streams into the flue gas channels.

An embodiment for coke oven chambers comprised of downcomer channels in side walls is described in WO 2009077082 A2. This invention relates to a device for feeding and controlling of secondary air from secondary air ducts into flue gas channels of horizontal coke oven chambers. The flue gas channels are located underneath the coke oven chamber floor on which coal carbonization is realized. Controlling elements which can precisely control the air flow into the flue gas channels are mounted in the connecting channels between the flue gas channels and secondary air ducts which serve for the supply of secondary air. The coke oven chamber is comprised of so-called “downcomer” channels for discharge of partially burnt gases from the carbonization process which are integrated in the lateral coke oven chamber wall, these “downcomer” channels connecting the coke oven chamber interior with the flue gas channels.

In most layouts, the number of downcomer channels in one coke oven chamber wall amounts up to 12, so a total of 24 downcomer channels can be provided per oven. The downcomer channels are downwards directed and in the majority of layouts, they are arranged in the walls of coke oven chambers because two walls each laterally enclose one coke oven chamber. In the upper section of a downcomer channel, the flow cross-section can be altered by means of an adjusting element, thus it is possible to adjust the effluent gas volume stream from a channel in longitudinal oven direction.

Partially burnt coke oven gas is composed of gas components, i.e. hydrogen, carbon monoxide, water, methane as well as, though in lesser portions, ethane, ethene, propane, propene and higher-grade hydrocarbons, for example benzene, toluene, xylene. Thus it contains volatile compounds which may condensate or pyrolyse in the downcomer channels and which lead to non-desired carbon deposits. Carbon deposits thus formed are composed of tar-laden, soot-forming compounds, and more particularly of graphite, and in the course of operating time these deposits may build-up in substantial quantities. In particular, these deposits accumulate in the downcomer channels in case temperatures in these channels are too low and if no further combustion air is admitted. Thereby, these deposits constrain or block the flow cross-sections of the downcomer channels.

U.S. Pat. No. 6,187,148 B1 describes a valve for a Non-Recovery coke oven through which the gas pressure in the interior of a coke oven chamber can be better controlled and whereby a supply of air into the downcomer channels is feasible. The valve has a rotating plug with a beveled end which progressively connects or disconnects the interior cavity of a coke oven chamber with the downcomer channel in order to control and regulate the gas pressure in the oven interior. By controlling the gas pressure, the volume of combustion air can be controlled as a function of the temperature gradients admitted into the oven. The combustion of a majority of the coal gas in the secondary heating spaces below the coke oven chamber, depending on the valve aperture degree, creates a thermal gradient through the coke oven chamber floor whereby coke quality is substantially improved. This publication does not describe the formation of deposits due to the pyrolysis of coke oven gas.

Owing to a combination of a low partial pressure of oxygen and a low temperature, these cracked hydrocarbon compounds preferably deposit at the entrance cross-sections or within the downcomer channels directed downwardly into the lower oven, for example in form of elementary carbon, graphite, tar, soot or similar compounds. Carbon-laden deposits pose a noticeable factor of interference for the operation of coke oven chambers. For example, such deposits constrain gas-conducting facilities so that the flow of gas for heating is slowed down or even prevented.

This problem has hitherto been solved virtually by feeding compressed air periodically into the downcomer channels, depending on the visual appearance of oven emissions and depending on the estimated oven performance rate, so that carbon deposits are removed from the cross-section by way of a compressed-air pulse. For this purpose, the lockable downcomer channel inspection ports arranged on the oven top are utilized to ensure access to the channels located underneath when being in open status. To clean these channels, operators manually blow compressed-air through a compressed-air lance into the inspection port for a certain period of time. Through the introduced compressed-air, carbon deposits in the further course of flow are burnt with the free OH radicals contained in air. The supply with compressed-air is ensured, for example, by way of a mobile compressor.

Though this manual procedure removes carbon deposits, it is liable to failures, because in a status when the oven doors are closed the entrance cross-section of the downcomer channels cannot be visually inspected during operation from the oven top. The concurrently reduced process velocity in turn frequently entails delays in the operational sequencing.

A permanent supply of air into the downcomer channels of the downwardly directed lateral chamber walls already leads to a complete combustion of the partially burnt crude gases and on account of the reduced heating performance associated therewith it is non-desired in flue gas channels further downstream underneath the oven chamber. As the downcomer channels are constrained or blocked, the negative pressure in the oven chamber above the coal is reduced or it may even happen that a positive pressure is developed. With a reduction of the negative pressure, the aspirated portion of air is reduced, and with a positive pressure, the required primary combustion air can no longer stream into the oven chamber. In this case, released crude gas escapes from primary air opening ports in the oven top and oven door, thereby causing a substantial ecological burden. Therefore, possibilities are searched for to either avoid or periodically remove such deposits. However, a visual monitoring is non-desired for practical and economic considerations.

Carbonization of coal according to the “Non-Recovery” or “Heat Recovery”—principle follows a distinct coking cycle in the course of which distinct values of temperature and pressure prevail at the relevant spots of a coke oven chamber. During coal carbonization, a certain amount of coal is charged at ambient temperature into the oven chamber to be charged and operated sub-stoichiometrically above the oven sole. Owing to this circumstance, a temperature drop which can be documented by thermocouples usually arranged in the oven chamber vault area initially occurs in this oven chamber.

In normal operation, after the charging procedure within a time interval of τ/τ_End=0 to 0.15, the temperature drop in an oven chamber is characterized in that a temperature minimum of the oven chamber temperature ranges between 800° C. and 1150° C., depending on the oven type. The ratio τ/τ_End corresponds to the standardized operating time of the oven. Starting from an initial temperature level of approx. 1000° C. to 1450° C. at the moment of charging the oven (τ/τ_End=0), the temperature in the oven chamber, depending on the oven type, falls shortly by approx. 200° C. to 350° C. During the subsequent time interval τ/τ_End=0.15 to 1.0, the oven chamber temperature again comes close to the initital temperature level.

DE 102006004669 A1 teaches a coking oven in flat construction style, a so-called non-recovery or heat-recovery coking oven which is comprised at least of a measuring device to measure the concentration of gas constituents of a coke oven chamber, coke oven sole and/or waste gas flue, and in which the optimal feed of primary and/or secondary air is determined and controlled via a process computer on the basis of these data. The invention also covers a coal carbonization process utilizing such a coking oven. The invention teaches the application of measuring parameters for automated control of the feed of combustion air, but it does not describe the removal of carbonaceous deposits with the peculiarities of this task.

The pressure in a coke oven chamber also varies in the course of the coke making process. “Non-recovery and heat-recovery” coke ovens operate in negative pressure mode, whereof an emission-friendly appearance is derived for this oven type. The level of the negative pressure in the chambers is usually adjusted and set through a suction blower or by exploiting the natural draft of a chimney so as to make a sufficient stream of air volume available for the combustion of the maximal crude gas volume stream escaping during the initial phase of coal carbonization in order to avoid flame-off losses and emissions through primary air opening ports and oven doors. Negative pressures in the oven chamber above the coal cake may range between −10 Pa and −100 Pa.

Thus there are indicators on the basis of which a periodical removal of carbonaceous coverings can be effected. Now, therefore, it is the object to perform a removal of carbonaceous coverings at suitable spots inside a coke oven chamber based on measured values for pressure and temperature. The removal of carbonaceous coverings is to be performed in the simplest possible manner in order to be able to perform a removal of these coverings without shutting down the coke oven chamber or even in running operation.

The present invention solves this task by providing for a method according to which compressed air is periodically conducted into the downcomer channels depending on at least one measuring parameter so that carbon deposits accumulating therein are removable by an injection of compressed air blown into the downcomer channel. Removal of coverings is accomplished by way of combustion in such a manner that the carbonaceous coverings react with the free OH radicals as well as with the oxygen of the gas introduced and that an additional suction and cleaning effect is achieved by the inlet pulse of compressed air. Injection of compressed air is performed with advantage through the inspection ports of the downcomer channels because these are easily accessible and because a retrofit is readily possible.

Control of air injection, for example, can be accomplished via a measurement of pressure at any spots of the coke oven chamber. However, the control of air injection, for example, can also be accomplished via a measurement of temperature at any spots of the coke oven chamber. The introduced compressed air contains the oxygen required to burn-off the coverings. A gas enriched with oxygen may also be utilized to implement the present invention.

Control of air injection, for example, can also be accomplished via an operationally optimized timer, whereby compressed air is injected within fixed time intervals for an optional period of time into the downcomer channel. The time intervals are then stipulated empirically, for example by evaluation of visual check-ups of the downcomer channels.

The present invention makes it possible to remove carbonaceous coverings during operation without requiring an interruption of operation or dismantling of a coke oven chamber. Air or oxygen-laden gas is conducted with the desired approach through measuring signals or upon expiry of a determined time interval into the downcomer channels so that a temporal introduction of oxygen-laden gas is effected. A partial cooling-down of the downcomer channels involved by an excessive or uncontrolled supply of oxygen-laden gas and entailing possible damage to a coke oven chamber is thus avoided.

Claim is laid in particular to a method for automatic removal of carbon deposits from coke oven chambers and flow channels in “Non-Recovery” and “Heat Recovery” coke ovens, wherein

• • a coke oven bank comprised of several coke oven chambers each comprised of two lateral coke oven chamber walls and downcomer channels arranged therein is supplied with compressed air through a compressed air mains,
    and which is characterized in that
  • a partial stream of compressed air is branched off into at least one coke oven chamber and streams into the downcomer channels and can be shut off, and
  • this partial stream of compressed air, depending on at least one measuring parameter, is periodically conducted into at least one downcomer channel so that carbon deposits accumulating therein are removable by a blow of compressed air injected into the downcomer channel.

This measuring parameter, for example, is a pressure parameter which is measured at least at one spot in the coke oven. It is then related to an already known design value or to another measurable pressure value. As a rule, one or two individual pressure parameters are thus measured. For example, the pressure parameter is a pressure differential measured in the combustion chambers below and above the coal and coke cake, i.e. between the primary heating space and the flue gas channels underneath the coke oven chamber and which amount to Δp>30 Pa to release and trigger the blow of compressed air injection. The pressure parameter may be a pressure differential measured between the gas space of a coke oven chamber, the primary heating space, and the ambient atmosphere, and which amounts to −70 Pa<Δp<40 Pa to release and trigger the blow of compressed air injection.

In case the downcomer channels are blocked due to a clogging upstream, then the pressure differential between both combustion chambers, i.e. between the primary heating space and the secondary heating space, empirically rise to values of ΔP>30. Due to the clogging, the secondary combustion process in the secondary air soles lacks the partially burnt coking gas. As a consequence, the coal charge is solely heated from above, i.e. by the heat from the primary combustion process This leads to a reduced process velocity which empirically results in a reduction of the oven performance rate.

The measuring parameter may also be a temperature parameter which is measured at least at one spot in the coke oven. This temperature parameter, for example, is the temperature measured in the gas space above the coke cake and which exceeds T=1100° C. to release and trigger the blow of compressed-air injection.

The control of air injection, for example, can also be accomplished via a timer according to fixed time intervals for certain time periods, without requiring an additional evaluation of measured values. The partial stream of compressed air is then periodically conducted with a fixed time interval into at least one downcomer channel so that carbon deposits accumulating therein are removable by an injection of compressed air blown into the downcomer channel. The time intervals are then stipulated empirically, for example by evaluation of visual check-ups of the downcomer channels.

The compressed air is for example a normal, non-dried air with an atmospheric composition. It is brought through a compressor to a pressure level that is suitable for introduction or injection into the inspection ports of the downcomer channels. However, the compressed air may also be air which is enriched with oxygen. In another embodiment of the present invention, the compressed air may also be replaced with pure oxygen. For better execution, the compressed air may also be enriched with combustion-inert gases. Hence, the compressed air may also be enriched with nitrogen or waste gas branched off from the combustion process. The medium may also be pure oxygen. Finally, the compressed air may be air which is mixed with the partially or completely burnt waste gas of the coke oven chamber. The medium is typically supplied at a positive pressure of 0.1 to 10 bar. The medium may be dried or non-dried.

To release and trigger the compressed air blow, the measuring values of the probes are advantageously picked-up, evaluated and controlled by a digital computer. To implement the present invention, it is already sufficient if the measuring value of at least one pressure or temperature parameter is picked-up, evaluated and controlled by a digital computer so that this computer depending on the measuring values turns on at least one blow of compressed air into an ancillary piping and the associated downcomer channels. But the computer may also turn on at least one blow of compressed air injection into a distribution mains and the associated downcomer channel depending on the measuring values.

It is also feasible to effect a periodical introduction of compressed air based upon empirical values. In one embodiment of the present invention, the measuring value represents an empirical determination of a time interval according to which this partial stream of compressed air is periodically conducted into at least one downcomer channel. As an example, the empirical values can be determined visually or by preceding measurements.

A removal of carbonaceous coverings can be performed at each downcomer channel of all coke oven chambers. But a removal of carbonaceous coverings can also be performed at individual downcomer channels of all coke oven chambers, at each downcomer of one coke oven bank only, or at each individual downcomer of just one coke oven bank. It is also conceivable to effect the removal of carbonaceous coverings at further spots of the coke oven chamber, although the downcomer channels represent the preferred place of applying the present invention.

Due to the large geometrical distance of several meters to the relevant downcomer channels located downstream, a removal of carbonaceous coverings by means of a prior art controlled elevated primary volume stream into the coke oven chamber yields no cleaning effect. For ovens with air supply through the top, this is reasoned by the fact that the primary air flow streaming through the oven top initially enters in normal direction into the coke oven chamber, said air stream being vertically directed downwards and striking there upon the coal cake surface. On this way further downwards, the oxygen concentration continuously decreases owing to combustion processes, and the residual oxygen concentration resting at the coal cake surface finally is so small that it does not cause any effects there in terms of combustion and removal of deposits due to the large distance to the downcomer channels.

A disproportional increase in primary air volume is not possible because the process requires sub-stoichiometrical conditions in the combustion chamber above the charge.

Claim is also laid to a device by way of which the inventive method can be implemented. Claim is laid in particular to a device for automatic removal of carbon deposits from coke oven chambers and flow channels in “Non-Recovery” and “Heat Recovery” coke ovens, the said device comprised of

• • a compressed-air mains installed on the oven top of a coke oven bank built-up of several coke oven chambers and connecting the coke oven chambers in transverse direction,
    and which is characterized in that
  • the compressed-air mains on the top is comprised of at least one branch which terminates in its further course into a pipe which in one downcomer channel is comprised of a pipe end to emit compressed air.

For example, the compressed air can be furnished by a compressor. It is then fed into a compressed air main. With advantage it extends transversely along the coke oven bank. This can be arranged at the level of the top of the coke oven bank. But for example, this can also be arranged at the level of service platforms of the oven sole located laterally at the oven front sides of the coke oven bank. Moreover, an arrangement of this line at the level of the ground floor is also conceivable.

The piping on the top of the coke oven bank is then comprised of a branch which terminates in its further course into an ancillary pipe extending in longitudinal oven direction from the pusher side to the coke side of the oven, and from which at least another piping branches off in the further course, said piping terminating into a pipe end which is suitable to emit compressed air in a downcomer channel.

To this effect, each coke oven chamber of a coke oven bank may have a branch at the transversely extending compressed air mains, said branch then leading in another branch into each downcomer of the coke oven chamber wall. However, it is also feasible that only one coke oven chamber has a branch from which all downcomer channels are supplied with compressed air in further branches. Furthermore, it is also feasible that each coke oven chamber has a branch at the transversely extending compressed air mains, whereby only one downcomer channel is furnished with compressed air. Finally it is feasible that only one piping on the top of the coke oven bank has a branch which in its further course terminates in an ancillary piping extending in longitudinal oven direction from pusher side to coke side of the oven, and from which only another distribution mains branches off in the further course of the flow route which terminates in a pipe end that is suitable to emit compressed air in a downcomer channel.

In a simple embodiment, it is also conceivable that a pipe end suitable to emit compressed air terminates in each downcomer channel of each coke oven chamber of a coke oven chamber bank.

In an embodiment of the inventive method, at least one pipe end has a built-on nozzle jet attachment which is suitable to eject a compressed air blow. In an advantageous layout, the outlet openings of the nozzle jet can be so configured that the compressed air streams at an angle to the vertical line greater than 0° into the cross-section of the downcomer aperture. In another embodiment of the inventive method, at least one pipe end is horizontally angled. As a result hereof, the pipe end which is suitable to eject a compressed air bow can be pointed to the entrance opening of the downcomer cross-section. In another embodiment, the outlet opening of the pipe end can be slotted, rectangular, annular or circular as well as include a combination of several outlet shapes of these. The pipe shapes or configurations for pipe ends as described hereinabove can be implemented at just one pipe or pipe end, but also at an arbitrary number of pipes or pipe ends.

On account of the high temperatures in the downcomer channel which range between 950 and 1500° C., the pipe end is made from any material that should be resistant to heat. In exemplary configurations, the pipe end is made from a heatproof iron material, a ceramic silica material, or a corundum material. Preferably this material is selected from the group of heat-resistant steels or refractory ceramic construction materials. Out of this group of construction materials, those materials especially suitable are, for example, materials especially rich in alumina as well as highly burnt materials based on the raw material corundum with Al₂O₃-portions ranging between 50-94%, SiO₂-portions ranging between 1.5-46%, Cr₂O₃-portions less than 29%, Fe₂O₃-portions less than 1.6% and ZrO₂-portions less than 32%, because these materials are characterized by a high temperature of application over 1500° C.

To control the stream of compressed air into an ancillary piping, the ancillary piping is comprised of an automatable valve cock element to serve as shutoff device to control the stream of compressed air. The ancillary piping may also be comprised of an automatable slide gate element to control and regulate the compressed air flow. The same holds for the pipe ends with our without a built-on nozzle jet attachment. To control the blow of injected compressed air, at least one pipe end with or without a built-on nozzle attachment may be comprised of an automatable valve cock element to control and regulate the flow of compressed air. But it is also feasible to choose an automatable slide gate element to control and regulate the flow of compressed air. Finally, the control of compressed air can be executed by any arbitrary control and/or regulating device.

All the shutoff devices which serve to control and regulate the compressed air flow can be actuated, for example, electrically, hydraulically or by compressed air. In an embodiment of the present invention, the element to control and regulate the compressed air flow is actuated hydraulically. In another embodiment of the present invention, the element to control and regulate the compressed air flow is actuated electrically. In another embodiment of the present invention, the element to control and regulate the compressed air flow is actuated pneumatically.

The arrangement of measured value probes on the oven top, for example, is taken in such a manner that pressure measuring probes for pressure measurement are conducted through the inspection ports into the downcomer channels of the coke oven chamber to be liberated from carbon deposits. But these can also be conducted into the primary heating space. For example, 1 to 24 pressure measuring probes for pressure measurement are conducted through the inspection ports into the downcomer channels of the coke oven chambers to be liberated from carbon deposits. However, for pressure measurement, it is also possible to conduct 1 to 3 pressure measuring probes through the oven top of the coke oven chamber to be liberated from carbon deposits. It is also feasible to conduct 1 to 2 pressure measuring probes for pressure measurement laterally through the oven chamber doors of the coke oven chamber to be liberated from carbon deposits. Finally, it is also feasible to conduct 1 to 4 pressure measuring probes for pressure measurement laterally through the front walls of the oven located above the coke oven chamber door and covering the primary heating space. In this manner, a comparative signal is available which takes a temperature or pressure measuring value at one spot located in the upper section of the coke oven chamber and connected with the primary heating space.

The arrangement of the other measuring value probes, for example, is done in such a manner that 1 to 4 pressure measuring probes for pressure measurement are conducted through the lateral front walls of the oven chamber located under the coke oven chamber door and covering the secondary heating space or into the secondary air sole. For pressure measurement, it is also feasible to conduct 1 to 8 pressure measuring probes through the lateral front walls of the oven chamber located under the coke oven chamber door and covering the secondary heating space or into the secondary air sole. It is also possible to arrange 1 to 2 pressure measuring probes for pressure measurement in the connecting channels between the secondary heating space under the coal cake and the waste gas collecting duct of the coke oven bank. It is furthermore possible to arrange 1 to 2 pressure measuring probes for pressure measurement in the waste gas collecting duct extending transversely to the coke oven bank on the oven top. It is also possible to arrange 1 to 2 pressure measuring probes for pressure measurement in the waste gas collecting duct extending transversely to the coke oven bank under the coke oven chamber doors. The figures indicated hereinabove should be understood as exemplary configurations, with it being possible to arrange individual or several pressure measuring probes at different positions, too.

Thus, the pressure measurements can also be taken in the connecting channels between the secondary heating chamber under the coal cake and the waste gas collecting duct of the coke oven bank. In one embodiment, there is an upwardly directed stream in these channels because the waste gas collecting duct is arranged on the oven top. In this form, they are therefore also designated as “uptake” channels and they are also arranged in the lateral coke oven walls, though between the downcomer channels. By arranging pressure measuring probes in the gas flow upstream and downstream of the deposits impeding proper flow through, it is then possible to determine a pressure differential as a measured value.

To serve as control signals, it is also feasible to determine temperature measuring values. With the coke oven chamber to be liberated from carbon deposits, at least one thermocouple is conducted in the vault crest of the coke oven chamber to be liberated from carbon deposits through the oven top or through the lateral oven doors above the coke cake. Furthermore, at least one thermocouple can be conducted into the gas space above the coke cake through the coke oven chamber doors of the coke oven chamber to be liberated from carbon deposits. It is also possible to conduct at least one thermocouple through the inspection ports into the downcomer channels of the coke oven chamber to be liberated from carbon deposits. Since no temperature differential versus another measuring value is needed to take-up the temperature measuring values, the installation of temperature measuring probes at just one of these positions is feasible. As a matter of fact, however, several temperature measuring probes may be provided for. At other positions, too, which are eligible for this purpose, an installation may be provided for. For example, this can also be effected at the coke oven chamber wall, even though this approach is less advantageous. A combined measurement and evaluation of temperature and pressure measuring signals is also conceivable.

The control signal can also be given according to a fixed time interval without measuring data acquisition. Thus, above all during the initial phase of coal carbonization which is characterized by particularly high rates of carbon deposits due to sub-stoichiometric conditions prevailing in the upper oven chamber, it is advantageous to inject compressed air within shorter time intervals, e.g. 10 hrs, 24 hrs, and 36 hrs after the charging procedure, into the downcomers, thereby counteracting a process retarding in a preventive approach.

In an advantageous embodiment of the present invention, The coke oven bank in which at least one coke oven chamber is to be liberated from carbonaceous coverings is equipped with a digital computer unit which acquires and evaluates the control values from at least one pressure sensor or one thermocouple, and which controls the compressed air unit so that at least one blow of injected compressed air is turned-on by means of this control unit depending on the measuring values. In one embodiment, only the control element per oven wall is actuated that isolates the ancillary pipe extending from pusher side to coke side from the main delivery pipe. In this case, the shutoff elements in the ancillary pipe are in open position and are automatically supplied with compressed air as soon as the evaluation unit transmits the signal for opening. In this case, the air volume per downcomer channel can be adjusted and set manually by means of the valve cock position or by way of a calibrating element.

In another embodiment of the present invention, at least one distribution main which branches off from the ancillary piping or one pipe end with or without built-on nozzle jet attachment is comprised of an automatable valve cock element to control and regulate the compressed air blow. In another embodiment of the present invention, at least one distribution main which branches off from the ancillary piping or one pipe end with or without built-on nozzle jet attachment is comprised of an automatable slide gate element to control and regulate the compressed air blow.

The present invention bears the advantage in that carbonaceous coverings and deposits forming in coke oven chambers of the “heat recovery” or “non-recovery” type during operation by pyrolysis of carbonaceous coking gases can be removed without any further operational interruption in a non-mechanical manner. A trouble-free operation of the coke oven chambers is thus feasible. An excessive supply of air and a resultant cooling-off of the downcomer channels are avoided because the feed is controlled by measuring values.

The invention is elucidated in greater detail by way of four drawings, with the inventive method not being confined to these embodiments.

FIG. 1 shows a coke oven chamber with laterally arranged downcomer channels which can be seen in a frontal view obliquely laterally from the top.

FIG. 2 shows a coke oven bank with an arrangement of two coke oven chambers which can be seen in a frontal view obliquely laterally from the top.

FIG. 3 shows a coke oven chamber in a lateral view, which is comprised of a waste gas collecting duct underneath the coke oven chamber doors.

FIG. 4 shows a coke oven chamber in a lateral view which is comprised of a waste gas collecting duct on the top of the coke oven chamber.

FIG. 1 shows a coke oven chamber (1) on which the coke oven chamber doors (2) have been removed so that the coke oven chamber opening (3) can be seen. To be seen in the coke oven chamber (1) is the coal cake (4) which is carbonized and which therefore develops coking gas (5). The coking gas (5) streams into the primary heating space (6) where it is mixed with a sub-stoichiometric volume of air and partially burnt. The partially burnt coking gas (7) streams through lateral openings (8) in the coke oven chamber wall (9) into the downcomer channels (10) where carbonaceous deposits (11) are formed due to the temperature level and the pyrolysis taking place under sub-stoichiometric conditions. From a compressed air main (12) extending transversely to the coke oven chamber (1), an ancillary piping (13) branches-off which extends longitudinally to the coke oven chamber (1). From this ancillary piping, in turn, pipes (14) branch off which feed the individual downcomer channels (10) with compressed air (15). These pipes (14) lead through the inspection opening ports (16) of the downcomer channels (10) in the top (17) of the coke oven chamber (1). The feed of compressed air (15) is controlled and regulated by a shutoff element (18) which in this case is a slide gate (18a). The slide gate is driven by an electrical control unit (18b) which is linked to a computer unit. Upon opening the slide gate (18a), air (15) or an oxygen-laden gas streams through the pipe end (19) into the downcomer channels (10). The compressed air mains (12) and the ancillary piping (13) are also isolated from each other by means of a controllable shutoff valve (18c) and a control unit (18d). The pipe end (19) may be arranged at any arbitrary level in the downcomer channel (10), but is preferably so arranged that the air (15) streams onto the spots (11) where empirically the majority of deposits accumulate. By means of a temporal and dosed feed of air (15), the carbonaceous deposits (11) in the downcomer channel (10) are burnt. Partly burnt coking gas is then passed into the secondary heating spaces (20) where it is completely burnt by the feed of further secondary air (21).

FIG. 2 shows an arrangement of two coke oven chambers (1) in a coke oven bank (22), above which a central compressed air main (12) extending transversely to the coke oven chambers (1) is arranged. From this compressed air main (12), an ancillary piping (13) branches-off which extends longitudinally to the coke oven chambers (1). From this ancillary piping, another distribution mains (14) branch off which feed the individual pipes (14) with compressed air (15). The distribution mains (14) are comprised of pipe ends (19), which terminate in the downcomer channels (10), where the oxygen-laden compressed air (15) leads to a combustion of carbonaceous coverings and deposits (11). Two of these pipe ends (19) are horizontally angled-off (19a). The distribution mains (14) are shut-off by shutoff elements (18), thus making it possible to control the feed of air into these distribution mains (14). In the primary heating room (6), the coking gases (5) streaming out from the coke cake (4) are burnt with a sub-stoichiometric volume of air, i.e. primary air (23). The combustion air (23) needed for this purpose is supplied through primary air opening ports (24) in the coke oven chamber top (25). The downcomer channels (10) take-up the partially burnt coking gas (7) from the primary heating space (6) and lead it into the secondary heating spaces (20) which are fed with air (21) via the secondary air soles (26). Waste gas from the secondary heating space (20) is conducted into the central waste gas duct (27).

FIG. 3 shows a coke oven chamber (1) in a lateral view. To be seen here are the frontal coke oven chamber doors (2), which are illustrated in an embodiment in which the coke oven chamber doors (2) are perfectly fitted into the coke oven chamber walls (28) located thereabove. From the coal or coke cake (4) the coking gas (5) streams into the primary heating space (6), from where it is conducted via opening ports (8) into the downcomer channels (10). From there it streams into the secondary heating spaces (20), where it is burnt through opening ports (20a, 20b) with secondary air coming from the secondary air soles (26). The completely burnt coking gas (29) is passed through a collecting duct (30) into a central waste gas main (27) where the waste gas (29) is collected and utilized in “Heat-Recovery” ovens for recovery of heat. The downcomer channels (10) may get clogged with carbonaceous coverings (11). Therefore, they are fed via a central compressed air main (12) and an ancillary piping (13) with compressed air which is distributed via distribution mains (14) with pipe ends (19) into the downcomer channels (10). Both the distribution main (14) and the pipe ends (19) can be shut-off via valves (18c, 18). The valves (18) in turn are linked to a digital computer unit (31) which is controlled through control signals from sensors (32). The sensors (32) are located in the primary heating space (6) of the coke oven chamber (1), where a pressure measuring sensor (32a) and a thermocouple (32b) are arranged, and in the secondary heating space (20) under the coke oven chamber (1), where also one pressure sensor (32a) and one thermocouple (32b) element each are arranged, and in the central waste gas main (27), where one pressure sensor (32a) each is arranged in the waste gas collecting duct (30) and in the central waste gas main (27). The measuring values of the sensors are picked-up by the digital computer unit (31) which will then activate the valves (18) of the compressed air mains leading into the downcomer channels (10). By supplying compressed air, the carbonaceous coverings (11) in the downcomer channels (10) are removed. For comparative purposes, two downcomer channels with carbonaceous coverings (11) are shown in the sketch.

FIG. 4 shows the same coke oven chamber (1) in a lateral view, but with a waste gas collecting duct (27) on the top (25) of the coke oven chamber. On the top (25) it also has a central compressed air mains (12), from where an ancillary piping (13) branches off and from where the individual distribution mains (14) with the pipe ends (19) branch off with the distribution main (14) into the downcomer channels (10). In the central waste gas main (27), which is installed here on the top (17) of the coke oven chamber (1), a pressure sensor (32a) is arranged. In the secondary heating space, there are two pressure measuring sensors (32a), and in the primary heating space, there are one pressure measuring sensor (32a) and one temperature measuring sensor (32b) each. Here, too, one can see carbonaceous coverings (11) at two downcomer channels (10) which are removed by the feed of compressed air (12).

LIST OF REFERENCE NUMERALS

1 Coke oven chamber
2 Frontal coke oven chamber doors
3 Coke oven chamber opening
4 Coke or coal cake

5 Coking gas

6 Primary heating space
7 Partially burnt coking gas
8 Openings of downcomer channels
9 Coke oven chamber wall
10 “Downcomer” channels
11 Carbonaceous deposits
12 Central compressed air mains
13 Ancillary piping
14 Piping as distribution main

15 Compressed air

16 Inspection opening ports
17 Top of coke oven chamber
18 Shutoff device
18a Slide gate
18b Electrical control device
18c Valve cock
18d Electrical control device
19 Pipe end of compressed air mains
19a Horizontally angled pipe end
20 Secondary heating spaces

21 Secondary air

22 Coke oven bank

23 Primary air

24 Primary air opening ports
25 Top of coke oven chamber
26 Secondary air soles
27 Central waste gas main
28 Coke oven chamber walls

29 Waste gas

30 Waste gas collecting duct
31 Digital computer unit
32 Measuring sensor
32a Pressure measuring sensor
32b Temperature measuring sensor

Claims

1. Method for automatic removal of carbon deposits (11) from oven chambers (1) and flow channels (10) of “Non-Recovery” and “Heat-Recovery” coke ovens, wherein

a coke oven bank (22) comprised of several coke oven chambers (1) having two lateral coke oven chamber walls (9) each and “downcomer” channels (10) arranged therein is supplied with compressed air (15) via compressed air main (19), characterized in that

a partial stream of compressed air (15) streaming into the “downcomer” channels (10) and being lockable is branched off into at least one coke oven chamber (1), and

this partial stream of compressed air (15) is periodically conducted into at least one “downcomer channel” (10) so that carbon deposits (11) contained therein can be removed by a compressed air blow (15) injected into the “downcomer” channel (10).

2. Method according to claim 11, characterized in that the measuring parameter is a pressure parameter measured at least at one spot in a coke oven (1).

3. Method according to claim 2, characterized in that the pressure parameter is a pressure differential measured in the combustion chambers (6,20) underneath and above the coal and coke cake (4), and which amounts to Δp>30 Pa to trigger the compressed air blow (15).

4. Method according to claim 2, characterized in that the pressure parameter is a pressure differential measured between the gas space (6) of the coke oven chamber (1) above the coal or coke cake (4) and the ambient atmosphere, and which amounts to −70 Pa<Δp<+40 Pa to trigger the compressed air blow (15).

5. Method according to any of the preceding claims 1 to 4, characterized in that the measuring parameter is a temperature parameter measured at least at one spot in the coke oven (1).

6. Method according to claim 5, characterized in that the temperature parameter is the temperature measured in the gas space (6) above the coke cake (4), and which is less than T=1100° C. to trigger the compressed air blow (15).

7. Method according to any of the preceding claims 1 to 6, characterized in that the compressed air (15) is air with an atmospheric composition.

8. Method according to any of the preceding claims 1 to 6, characterized in that the compressed air (15) is air which is enriched with oxygen.

9. Method according to any of the preceding claims 1 to 6, characterized in that the compressed air (15) is replaced with pure oxygen.

10. Method according to any of the preceding claims 1 to 6, characterized in that the compressed air (15) is air which is enriched with nitrogen.

11. Method according to any of the preceding claims 1 to 6, characterized in that the compressed air (15) is air which is mixed with the partially or completely burnt waste gas (29) of the coke oven chamber (1).

12. Method according to any of the preceding claims 1 to 11, characterized in that the measuring value of at least one pressure or temperature measuring parameter is recorded, evaluated, and controlled by a digital computer unit (31) so that this computer unit (31) depending on the measuring values turns-on at least one compressed air blow (15) into an ancillary piping (13) and the associated “downcomer” channels (10).

13. Method according to any of the preceding claims 1 to 12, characterized in that the measuring value of at least one pressure or temperature measuring parameter is recorded, evaluated, and controlled by a digital computer unit (31) so that this computer unit (31) depending on the measuring values turns-on at least one compressed air blow (15) into a distribution mains (14) and the associated “downcomer” channels (10).

14. Method according to any of the preceding claims 1 to 13, characterized in that the measuring value represents an empirical determination of a time interval, according to which this partial stream of compressed air (15) is periodically conducted into at least one “downcomer channel ” (10).

15. Device for automatic removal of carbon deposits (11) from coke oven chambers (1) and flow channels (10) of “Non-Recovery” and “Heat-Recovery”—coke ovens, the said device comprised of

a compressed air mains installed (12) installed on the oven top (17) of a coke oven bank built-up of several coke oven chambers (1) and connecting the coke oven chambers (1) to each other in transverse direction,

characterized in that the compressed air mains (12) on the top (17) is comprised of at least one branch which in the further course of flow terminates in a lockable ancillary piping (13) which in a “downcomer” channel (10) arranged in a lateral coke oven wall (9) has a pipe end to emit compressed air (15).

16. Device according to claim 15, characterized in that the compressed air main (12) on the top (17) of the coke oven bank has at least one branch which in the further course of flow terminates in a lockable ancillary piping (13) which extends in longitudinal oven direction from the pusher side to the coke side of the oven (1), and from which in the further course of flow at least another distribution main (14) branches off which terminates in a pipe end (19) arranged in a “downcomer” channel (10) and which is suitable to emit compressed air (15).

17. Device according to any of the preceding claim 15 or 16, characterized in that a pipe end (19) which is suitable to emit compressed air (12) terminates in each “downcomer” channel (10) of each coke oven chamber (1) of a coke oven chamber bank.

18. Device according to any of the preceding claims 15 to 17, characterized in that at least one pipe end (19) is comprised of a built-on nozzle jet attachment which is suitable to eject a compressed air blow (15).

19. Device according to any of the preceding claims 15 to 18, characterized in that at least one pipe end (19) is horizontally angled.

20. Device according to any of the preceding claims 15 to 19, characterized in that the pipe end is made from a heat-resistant iron material.

21. Device according to any of the preceding claims 15 to 19, characterized in that the pipe end is made from a ceramic silica material.

22. Device according to any of the preceding claims 15 to 19, characterized in that the pipe end is made from a corundum material.

23. Device according to any of the preceding claims 15 to 22, characterized in that the ancilllary piping (13) has an automatable valve cock element (18c) serving as shutoff device (18) to control the compressed air flow (15).

24. Device according to any of the preceding claims 15 to 22, characterized in that the ancilllary piping (13) has an automatable slide gate element (18a) serving as shutoff device (18) to control the compressed air flow (15).

25. Device according to any of the preceding claims 15 to 22, characterized in that at least one pipe end (19) with or without a built-on nozzle jet attachment has an automatable valve cock element (18c) serving as shutoff device (18) to control the compressed air flow.

26. Device according to any of the preceding claims 15 to 22, characterized in that at least one pipe end (19) with or without a built-on nozzle jet attachment has an automatable slide gate element (18a) serving as shutoff device (18) to control the compressed air flow.

27. Device according to any of the preceding claims 15 to 26, characterized in that the shutoff device (18) to control the compressed air flow (15) is hydraulically actuated.

28. Device according to any of the preceding claims 15 to 26, characterized in that the shutoff device (18) to control the compressed air flow (15) is electrically actuated.

29. Device according to any of the preceding claims 15 to 26, characterized in that the shutoff device (18) to control the compressed air flow (15) is pneumatically actuated.

30. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 24 pressure measuring probes (32a) for pressure measurement are guided through the inspection opening ports (16) into the “downcomer” channels (10) of the coke oven chamber (1) to be liberated from carbon deposits (11).

31. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 3 pressure measuring probes (32a) for pressure measurement are guided through the oven top (17) of the coke oven chamber (1) to be liberated from carbon deposits (11).

32. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 2 pressure measuring probes (32a) for pressure measurement are guided through the coke oven chamber doors (2) of the coke oven chamber (1) to be liberated from carbon deposits (11).

33. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 4 pressure measuring probes (32a) for pressure measurement are guided through the lateral front walls (28) of the oven chamber (1) which are located above the coke oven chamber door (2) and cover the primary heating space (6).

34. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 8 pressure measuring probes (32a) for pressure measurement are guided through the lateral front walls (9) of the oven chamber (1), which are located underneath the coke oven chamber door (2) and cover the secondary heating space (20) or in the secondary air sole (26).

35. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 2 pressure measuring probes (32a) for pressure measurement are arranged in the connecting channels (20a) between the secondary heating space (20) underneath the coal cake (4) and the waste gas collecting duct (26) of the coke oven bank.

36. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 2 pressure measuring probes (32a) for pressure measurement are arranged in the waste gas collecting duct (26) which extends transversely to the coke oven bank on the oven top (17).

37. Device according to any of the preceding claims 15 to 29, characterized in that 1 to 2 pressure measuring probes (32a) for pressure measurement are arranged in the waste gas collecting duct (26) which extends transversely to the coke oven bank underneath the coke oven chamber doors (2).

38. Device according to any of the preceding claims 15 to 37, characterized in that at least one thermocouple (32b) is guided into the gas space (6) above the coke cake (1) through the coke oven chamber doors (2) of the coke oven chamber (1) to be liberated from carbon deposits (11).

39. Device according to any of the preceding claims 15 to 37, characterized in that at least one thermocouple (32b) is guided through the inspection opening ports (16) into the “downcomer” channels (10) of the coke oven chamber (1) to be liberated from carbon deposits (11).

40. Device according to any of the preceding claims 15 to 37, characterized in that at least one thermocouple (32b) is guided at the vault crest through the oven top (17) the coke oven chamber (1) to be liberated from carbon deposits (11).

41. Device according to any of the preceding claims 15 to 40, characterized in that the said device has a digital computer unit (31) which records, evaluates and controls the control values of at least one pressure sensor (32a) or one thermocouple (32b) so that by means of this control unit (31), depending on the measuring values, at least one compressed air blow (15) in the ancillary piping (13) and in at least one downcomer channel (10) is turned on.