Patent Application
20140054157
The invention relates to a contrivance for regulating the chamber pressure of coke oven chambers in a coke oven battery by means of adjustable iris diaphragms or iris nozzles at the standpipe gooseneck outlet openings to the crude gas collecting main. The contrivance allows the flow rate of the gas stream flowing from the gas space of a coke oven chamber into the crude gas collecting main to be regulated, thus allowing the pressure in the gas space of the coke oven chamber to be adjusted. The invention also pertains to a method for regulating the gas flow from the gas space of a coke oven chamber, whereby the pressure in the coke oven chamber is regulated as a result thereof.
During the production of coke, coke oven gases are formed during the coking process. These lead to a pressure increase in the gas space of the coke oven chamber. The pressure in the gas space is very much dependent, among other things, on the progress of the coking process so, depending on the type of coke oven, considerable pressure may build up in the gas space. For this reason, if a chamber pressure control system is used in conventional-type coke ovens, the coking gas is conveyed to a negative pressure-operated crude gas collecting main which extracts the coking gas for subsequent use. There is usually a certain water level in the crude gas collecting main as the crude gases from the coke oven chamber are impacted with water for gas scrubbing purposes. Particles or entrained impurities can also be trapped and removed in this way.
The gas flows from the coke oven chamber into the crude gas collecting main via a standpipe which, in a typical embodiment, branches into an gooseneck and then passes into the crude gas collecting main via a vertical connector. For scrubbing purposes, water is fed or injected into the gooseneck and the connector to the collecting main. In order to regulate the pressure, it is therefore necessary to ensure that the water is continuously discharged or can at least be discharged at regular intervals.
EP 649455 B1 describes a method for regulating or controlling the gas pressure of a coke oven battery, in which a cup-shaped restrictor element that can be filled with water is operated in accordance with the pressure variation during the formation of gas from the coal to be coked, each individual oven being restricted by adjusting the water level in the restrictor element as a function of the actual pressure conditions in the respective coke oven chamber in such a manner that, depending on the desired gas pressure in the coke oven chamber, the water level is adjusted as a function of the outflow or inflow of the water from or into the cup-shaped restrictor element or as a function of a predeterminable overflow level. The gas pressure is regulated via a swivel cup with one or more water outlets between the cup base and the cup rim, said cup being located below a rising pipe bend and designed so that it can be filled with varying amounts of water via a coal water line comprising a valve which is connected via operating devices and a computer to pressure measuring points. The method has the disadvantage that the oven pressure is regulated via a variable water level in an immersion cup and regulation of the water level thus depends on the volumetric flow rate of the collecting main scrubbing liquid which is supplied to the immersion cup via the relevant water feed nozzles and which at times may therefore be low, meaning that the water level falls below the minimum required for gas cooling and the crude gas is not cooled sufficiently.
EP 1390440 B1 describes a contrivance for regulating the gas pressure in a coke oven chamber comprising an immersion cup to which water is supplied and an immersion pipe which is connected to the gas space of the coke oven chamber and which terminates in the immersion cup, wherein the immersion cup has an overflow and a closable outflow and wherein the immersion pipe is designed with an end section, the free gas outlet cross section of which depends on the liquid level in the immersion cup, whereby the liquid level can be regulated by a run-off pipe for water, the inlet end of which protrudes into the immersion pipe, said run-off pipe having jacket-sided inlet openings for the water feed and there being a slide that is open on both sides located in the run-off pipe, said slide closing off the inlet openings of the run-off pipe in longitudinal direction according to its position and forming a vertically adjustable overflow for the water flowing into the run-off pipe, and the inlet end of the run-off pipe being enclosed by a siphon pipe which closes off the run-off pipe at the top and forms an annular channel that opens into the immersion cup below the immersion pipe so that water can flow in. Again, this contrivance and the process it operates have the disadvantage of being dependent on the water inflow always allowing a certain water level to be built up in the immersion cup. Unlike in the above-mentioned EP 649455 B1, the water inflow rate is constant and is not regulated, making it possible, with a certain amount of effort, to control susceptibility to contamination by gas condensates as there is no need for a control valve in the inflowing water stream.
Feeding water into the crude gas collecting main serves to maintain a flow of liquid through which the gas pressure in the coke oven chamber can be regulated. If the coke oven gas pressure is too low, air will penetrate into the coke oven chamber and the combustion of coal or coke oven gas may lead to overheating and consequently, to the coke oven chamber being damaged. Too high a pressure causes unwanted emissions of coke oven gas into the environment. Moreover, the water added to the standpipe or the standpipe gooseneck also serves as scrubbing water, removing particles and condensable constituents, such as tar, from the discharged coke oven gas. It is thus desirable to achieve a continuous water flow into the crude gas collecting main without influencing gas pressure regulation.
Therefore, the objective is to provide a gas-pressure-regulating contrivance which is not dependent on the water inflow and still allows water to flow from the standpipe into the crude gas collecting main via the regulating contrivance. The regulating contrivance should not be affected by the coke oven gases and still allow the coke oven crude gases to mix thoroughly with the water or a liquid. On closure of the regulating contrivance, a residual water flow should still be maintained to ensure that the scrubbing liquid discharges into the crude gas collecting main to prevent it from accumulating and flowing back into the coke oven chamber. On the other hand, it must also be ensured that the gas-regulating contrivance closes reliably to prevent negative pressure being created in the coke oven chamber, which would suck air into the gas collecting space and from there into the crude gas collecting main.
The invention achieves this objective by means of an adjustable diaphragm for regulating the gas and liquid flow into the gas collecting main so that it is possible to adjust the flow rate of the mass flow passing through the adjustable diaphragm. The diaphragm may be designed as a horizontally mounted, horizontally opening diaphragm that shuts off the cross section of the standpipe gooseneck in horizontal direction like a photographic diaphragm (also termed “iris diaphragm”). The diaphragm may also be designed as a horizontally mounted, but vertically opening, diaphragm, the petals of which, for example, fold down when the diaphragm opens (also termed “iris nozzle”).
Inside the standpipe gooseneck there may be a siphon, which, for example, may be suspended at the side of the standpipe gooseneck or in the middle of the standpipe gooseneck. In this way, the scrubbing liquid that is injected into the gooseneck can be discharged at all times. However, it is also possible to omit the siphon, in which case the adjustable diaphragm is designed to leave a slight opening in the cross section. This slight opening allows the liquid injected into the gooseneck to be drained into the crude gas collecting main even if there is no siphon.
What is claimed in particular is a contrivance for regulating the chamber pressure of coke oven chambers in a coke oven battery by means of adjustable diaphragms at the standpipe gooseneck outlet openings to the crude gas collecting main, comprising
In a typical embodiment of the invention the opening with the closure at the gooseneck is a cover plate that for closure is fitted to the opening at the top end above the gooseneck branch, said cover plate being equipped with a grasp for operation and a hinge at the gooseneck. During normal operation this serves to equalise the coke oven chamber pressure with respect to the outside pressure towards the end of the coking time prior to opening the coke oven chamber doors, and also to clean tar deposits from the standpipe. A cover plate fitted to the top end of the gooseneck is the most advantageous embodiment although in an exemplary embodiment a slide that opens sideways is also conceivable.
In an exemplary embodiment the diaphragm consists of plates that can be closed in a concentric, tangential and circular manner towards the centre of the standpipe. This corresponds to an embodiment which is comparable to a photographic diaphragm. For opening or closing, these plates are then moved in horizontal direction towards the centre of the pipe. There can be any number of plates and these can be of any size. Also the diaphragms can be of any number in the standpipe. The important thing is that the plate material is resistant to the prevailing temperatures and gas or liquid components. One embodiment regarding diaphragms that close in a tangential and circular manner towards the centre of a pipe (“iris diaphragms”) is known from U.S. Pat. No. 4,094,492 A. However, this specification does not describe oven pressure regulation at the goosenecks branching off coke oven chamber standpipes and the special requirements that result, such as high temperatures, water flow through the diaphragm and sealing of the coke oven chamber to prevent negative pressure entering.
The diaphragms in the gooseneck pipe are typically connected to an actuator, by means of which they can be moved from the outside. In one embodiment of the method, the plates are fitted with pins, all of which are mounted in a specially provided slotted opening or flexible connection to a ring positioned above so that the plates and with them the diaphragm opens or closes when the ring moves. The ring, which is in the pipe, is then tightened or released from the outside, causing the pins to move the plates, thus opening or closing the pipe. This allows the diameter of the diaphragm opening to be regulated.
A further embodiment envisages a diaphragm consisting of plates that can be closed in a concentric, secantial and direct manner towards the centre of the standpipe. These may, for example, be plates that are moved from the outer edge of the diaphragm to the centre of the standpipe gooseneck until said plates close to form a ring-shaped disc with a central aperture or a disc that is completely shut. For opening or closing, these are then moved in horizontal direction. Again, there may be any number of plates and these can be any size and made of any material.
Again, these diaphragms in the gooseneck pipe are typically connected to a regulating device which allows them to be moved from the outside. In one embodiment, the plates are fitted with pins. The pins can be pulled out of the gooseneck or the middle of the gooseneck pipe by means of levers extending through the gooseneck wall to the outside so that the plates and with them the diaphragms open or close when the lever is moved. This allows the diameter of the diaphragm opening to be regulated.
A further embodiment envisages the diaphragms consisting of plates that are opened by being swung up or down in vertical direction. In this case, the plates are designed as petals that are preferably pulled down in the direction of flow by an actuator. This is consistent with an embodiment that is comparable to a funnel diaphragm. The further the petals are pulled down, the wider the diaphragm opens. Again, there may be any number of diaphragms and these can be any size and made of any material. An embodiment for diaphragms that are opened by being swung up or down in the pipe in vertical direction (“iris nozzles”) are known from DE 10002529 A1. However, this specification again does not describe pressure regulation at the goosenecks branching off coke oven chamber standpipes and the special requirements that result, such as high temperatures, water flow through the diaphragm and sealing of the coke oven chamber to prevent negative pressure entering.
A further embodiment envisages the diaphragms being equipped with a circumferential ring that can be tightened or released by a regulating device via a transmission lever, thus pulling the plates up or letting them down and opening or closing the diaphragm with the gooseneck. This also allows the diameter of the diaphragm opening to be regulated. In a simple embodiment, this ring is designed as a wire which is threaded through retainer hooks in the diaphragms so as to encircle said diaphragms. The mechanical drive of the regulating device can be of any design and the way in which the actuating pulse is transmitted can be left to the technician.
In an exemplary embodiment the diaphragm can be adjusted by means of an electric regulating device. A further embodiment envisages the diaphragm being adjusted by means of a pneumatic regulating device. In a simple embodiment a manual actuator or regulating device is also conceivable.
The diaphragms and the actuator may be located in a gooseneck pipe section that can be removed from the gooseneck. For this, the removable pipe section can, for example, be flanged to the gooseneck.
In a preferred embodiment the contrivance is equipped with a siphon. However, it is also possible to equip the outlet section with a siphon that runs through the middle of the standpipe gooseneck and is enclosed by the diaphragm when closed. This allows the water flow to continue even when the diaphragm is closed. The standpipe gooseneck can also be equipped with a siphon at the side that laterally passes the standpipe gooseneck outside of the standpipe. This allows liquid to pass through even when the diaphragm is completely closed.
The siphon may be designed in any way. It may, for example, be designed as a simple S-shaped pipe but also as a double-walled pipe with an inside opening. It may also be equipped with separate conveying devices. The siphon may be made of any material and be of any type.
In one embodiment of the method the gooseneck pipe with the diaphragms has a diameter of 0.25 m to 0.85 m measured at the point where the diaphragms are located but excluding said diaphragms. However, it is possible to implement the method with any size diameter. In one embodiment of the invention the standpipe that is connected to the gooseneck has a cover plate above the branch, said cover plate being able to be opened and closed. During normal operation this serves to equalise the coke oven chamber pressure with respect to the outside pressure towards the end of the coking time prior to opening the coke oven chamber doors and to clean tar deposits from the standpipe.
The invention also relates to a method for regulating the gas flow from a coke oven chamber into a crude gas collecting main. What is claimed, in particular, is a method for regulating the chamber pressure of coke oven chambers in a coke oven battery by means of adjustable diaphragms at the standpipe gooseneck outlet openings to the crude gas collecting main, wherein
Typically, the coke oven gas flows into the standpipe gooseneck at a temperature of 700° C. to 1100° C. and is cooled immediately after entry by injecting liquid. The remaining liquid is then discharged into the crude gas collecting main. After cooling, the gas typically still has a temperature of between 75° C. and 120° C. as can be shown by measuring the temperature.
The process can be designed so that the diaphragm is controlled as a function of the internal pressure of the coke oven chamber, thus allowing the opening and closing of the diaphragm to be controlled in accordance with a typical coking cycle. When charging the coke oven chamber, the diaphragm is opened fully so that the charging gases can be sucked into the crude gas collecting main by the negative pressure that prevails in this main. During the coking cycle the pressure in the coke oven chamber is regulated so as to ensure that there is an optimum desired value in the gas space of the coke oven chamber at all times. When pushing the carbonised coke out of the coke oven chamber, the passage of the gas from the coke oven chamber to the crude gas collecting main is interrupted by partial or complete closure of the diaphragms. In this way air is prevented from entering the crude gas collecting main (so-called “uncoupling of the coke oven chamber from the crude gas collecting main”). During this operation, the liquid can continue to flow into the crude gas collecting main via the siphon if the diaphragm is not provided with a slight opening in it. This permits an optimum pressure setting in the coke oven chamber at all times, regardless of the liquid flow into the standpipe. Preferably, opening and closing of the diaphragm may be controlled by a computer.
The method and the device may be set so that, if the drive fails, the actuator remains in the control position it was last in. Overpressurisation in the coke oven chamber can thus be counteracted as the pressure in the coke oven chamber normally drops during the coking process. In such case any unwanted drop in pressure in the coke oven chamber can be neutralised by increasing the pressure in the collecting main. By this way, it is possible to regulate the gas pressure in the gas space of the coke oven chamber by altering the negative pressure in the crude gas collecting main, if the control mechanism drive fails.
In many embodiments the standpipe that is connected to the gooseneck has a cover plate above the branch that during normal operation serves to equalise the coke oven chamber pressure with respect to the outside pressure towards the end of the coking time prior to opening the coke oven chamber doors, and to clean tar deposits from the standpipe. In one embodiment of the invention the cover plate of the standpipe above the branch is temporarily opened while simultaneously closing the diaphragm when the doors of the coke oven chamber are opened. By closing the diaphragm air is prevented from being sucked in through the gooseneck as a result of the negative pressure in the crude gas collecting main and the crude gas collecting main is sealed off from the surroundings. One embodiment envisages the possibility of pneumatically opening or closing the cover plate located in the standpipe above the branch.
The regulating device for the diaphragms or the cover plate may, for example, be moved by means of an electric drive. However, it may also be moved, for example, by a pneumatic drive. In a simple embodiment it is also conceivable for the cover plate or the diaphragm to be moved manually. One embodiment of the invention envisages the pneumatic drive being powered by a nitrogen-containing gas. Another embodiment envisages the pneumatic drive being powered by air or by an air-containing gas.
The liquid introduced into the gooseneck may be any kind. Preferably, it is water. This serves to transport the particles and scrub the coke oven gases. One embodiment envisages the water containing ammonia. A computer-controlled unit can be used to control the regulating device. This may, for example, be deployed in the gooseneck as a function of pressure. For this purpose, an exemplary embodiment envisages a pressure line in the gooseneck that transmits the pressure in the gooseneck to a pressure sensor.
The advantage of the invention is to provide a regulated gas flow from the coke oven chamber to the crude gas collecting main that does not depend on the inflow of water or liquid and still allows liquid to flow from the standpipe into the crude gas collecting main via the regulating contrivance. The regulation thus still allows the coke oven crude gases to mix thoroughly with the water or a liquid when the diaphragm is closed. On closure of the regulating contrivance, a residual water flow is maintained to ensure that the scrubbing liquid drains into the crude gas collecting main. If a suitable construction manner of the diaphragm is selected, the regulating contrivance can be reliably closed at all times.
The invention is illustrated on the basis of eleven diagrams, these diagrams merely depicting embodiments of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 035 154.7 | Aug 2010 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2011/004112 | 8/16/2011 | WO | 00 | 5/8/2013 |
