MX2008010017A - Method and device for the coking of high volatility coal - Google Patents

Abstract

The invention relates to a method for the coking of coal, in particular coal with a high or alternating volatility, in coking plants comprising coking chambers, according to the non-recovery method or the heat recovery method. The invention also relates to a device, which can be used to carry out said method simply, as the overheating of the coking furnace is prevented by the injection of water vapour. If a battery of coking furnaces is used, the disclosed method can be carried out irrespective of the number of said furnaces.

Description

METHOD AND DEVICE FOR THE COCHIFICATION OF HIGH VOLATILITY CARBON DESCRIPTIVE MEMORY This invention relates to a method for the coking of coal, in particular coal with a high content or varied content of volatile matter, in coke processing plants with coking chambers using the non-recovery process or the heat recovery process, and in addition to a device required to implement this procedure by a very simple method to prevent the coke oven from overheating by supplying water vapor. The method mentioned in this application is independent of the number of coke ovens used, provided that the latter forms a battery. For coke processing, the preheated coking chamber of the coke oven is filled with a charcoal bed and closed after that. Said coal bed may consist of a charge of bulk coal or a load of compacted, die-cut coal. The heating of the coal causes the volatilization of the volatile matter contained in the coal, that is, mainly hydrocarbons. The heat also obtained in the coking chamber of non-recovery coke ovens and heat recovery coke ovens is generated exclusively by combustion of the liberated volatile carbon constituents that are volatilized successively by the advance heating process. In accordance with the prior art technology, combustion is controlled to ensure that part of the liberated gas that is also denoted as raw gas burns in the coking chamber directly above the char charge. The combustion air required for this purpose is sucked through the opening ports in the doors of the coke oven and roof of the furnace. This combustion stage is also denoted as the first air stage or primary air stage. Generally, the primary air stage does not lead to complete combustion. The heat released during combustion reheats the coal bed, with a layer of ash that forms on its surface after a short period. This layer of ash provides an exclusion of air, thus preventing the burning of the coal bed in the further course of the coke-making process. Due to the heat radiation from above through the developing ash layer, part of the heat released during combustion is transferred to the coal charge. Another part of the generated heat is transferred, predominantly by the conduction of heat through walls of the brick coke oven, into the coal bed. A mere heating of the carbon bed from the top, applying only a single air stage, however, can lead to inexpensively long coking times.

Therefore, the crude gas that is partially burned in the primary air stage is burned in another stage, thus supplying heat to the coal bed from the bottom or from the side. There are two technologies particularly known from the prior art: E.U.A. 4,124,450 in conjunction with the E.U.A. 4,045,299 and E.U.A. 3,912,597 of the same inventor, which describe how to pass the hot mixture of combustion waste gas and partially burn the raw gas in channels below the coking chamber where it can dissipate part of this heat to the brickwork located below the coal bed and transfer this thermal energy by conducting heat to the coal. A subsequent combustion in a recuperatively operated combustion chamber disposed between the side walls of the coker chamber is carried out in the course of additional flow. Due to the thermal conduction, the heat generated there is transferred laterally by means of the walls of the coke oven to the coal bed, thus substantially reducing the coking time. Said combustion stage it is also denoted as the second air stage or secondary air stage. The other technology of the prior art supplies the partially burned gas in the primary stage by means of channels located in the walls of the coke oven and is also denoted as "vertical down pipe" to the heating ducts in the brick hearth of the Furnace below the coking chamber where sufficient combustion air is continuously sucked to achieve complete combustion. As a result of what same, the coal charge is supplied with heat both directly by heat radiation from the upper part and indirectly by heat conduction from the lower part, thereby increasing the coking rate and the production speed of the furnace substantially. According to the prior art in the technology, the combustion gases that are released as a result of the combustion of two stages in the coke oven subsequently pass through the combustion gas channels located outside the coke oven to the chimney and can be evacuated into the atmosphere, as in the process without recovery, or, in the case of the heat recovery process, can be passed over, for example, another plant unit to generate steam. It is problematic that the release of the volatile carbon constituents does not proceed uniformly through the coking time. At the start of coke processing, a drop in the ambient temperature of the coke oven must be recorded. This is caused by the coal loading process, since the coal is charged at room temperature in the hot coke oven chamber. Subsequently, a phase of violent release of high-calorific gas follows. This instantaneous supply of heat in the coke oven can be absorbed by the coal and building materials of the coke oven at a limited speed only. Therefore, the temperature in the coke oven chamber rises in the course of the coke-making process, and if the charge coal mixture It has a high content of volatile matter, this can lead to exceeding the limit application temperatures of improved construction materials of the coke oven or combustion gas channels and plant units further located downstream. In the further course of the coking time, the release of the volatile carbon constituents becomes increasingly weak. According to the prior art in technology, the temperature in a coke oven is only controlled and regulated in the process by controlling and regulating the volumetric flow of the primary and secondary air. This has the disadvantage that an effect on the reaction of coke processing by itself is thus taken, since the oxygen contained in the primary and secondary air acts as a reaction partner and due to its presence over-stoichiometric or sub -stoichiometric leads to different stages of combustion. To avoid such problems and ensure a more uniform heat generation and a possible coke quality, a coal mixture of several individual carbon constituents is charged to the coke oven. The carbon mixture is conventionally adjusted to limit the volatile matter content by a certain maximum value. Since a substantial portion of the carbon resources available globally does not meet this criterion, the availability of coal suitable for this coke processing process is restricted by this approach, leading to economic disadvantages.

Therefore, now, it is the object of the invention to provide an improved method that does not represent restrictions for the coal with respect to its content of volatile matter, leading to a reduction in the amount of nitric oxides in flue gas, and preserving the material of the coke oven without causing any interruption in the speed of production of specific coke. This invention achieves this objective as defined in the main claim by applying a method for producing coke in a coking chamber of the non-recovery type or the heat recovery type, wherein: the coking chamber is charged with a coal bed where the coal is subsequently heated, thereby providing a volatilization of constituents of volatile carbon coal, • these constituents of volatile coal are partially oxidized by means of supplied air (primary air), • these gas mixing streams through the combustion gas channels in the brick hearth of the coke oven, where • the channels are arranged in the side walls of the coking chamber and the constituents of unburned volatile coal are burned in the brick hearth of the coke oven, where both the coking chamber and the brick hearth of the coke oven have installations to restrict the air supply, with the measured temperature and water vapor introduced into the coke oven for cooling, if required. A useful embodiment of this invention provides measurement of the temperature in the coking chamber and introduces water vapor for cooling, if required, in the gas space of the coking chamber, ie, above the coke cake. In another useful variant, steam is introduced, if required, into the combustion gas channels to cool the brick hearth of the coke oven. This method can also be optimized by applying these two variants together. The method presented by this invention is applied to ensure through the control of the water vapor supply that the maximum temperature at which the building materials of the coke oven are exposed does not exceed 1400 ° C. In the method of this invention, the water vapor has a high pressure to which it is supplied in the coking chamber and / or combustion gas pipes. In addition, the method can also be improved by using relatively cold water vapor, whose temperature is on a scale of 150 ° C to 300 ° C. Although low vapor temperatures are important to allow for the best possible energy absorption and an emission of energy from the coke oven, it has become evident that water vapor should not be introduced with too high an impulse in the coking chamber, otherwise the layer of ash that forms above the coke cake or coke charge wears out. This layer of ash serves as a important protective function for the valuable substance as it prevents the burning of coal and / or coke in the coke oven. An improvement resides in introducing water vapor together with primary air and secondary air, respectively, making it possible to reduce the number of ports of opening in the construction structure of the coke oven. This invention also encompasses a coke oven for applying this method in one of the described embodiments, providing opening ports in the coke oven in the wall of the coke oven or combustion gas channels through which steam can be introduced. of water. An improvement of the coke oven resides in that a central steam line leads to these opening ports and in which several coke ovens are connected to each other. In an improved variant of this coke oven, the measuring devices designed to vary the required volume of water vapor are installed upstream of these opening ports or in the lines, and these measuring devices in turn are connected by means of from control lines to a procedure computer. It is not required to introduce this water vapor through the entire coking time of a coal charge. It is mainly necessary to introduce water vapor at the beginning of and during the heating phase. When a critical ambient temperature of the coke oven is reached, the method described hereinabove is successfully applied to achieve a moderate restriction. Since the temperature of the coke oven can be maintained very precisely at a safe but high level by introducing water vapor, and since the water vapor behaves in an inert manner in the coke oven or in the steps of the ordinary process below, the coking process as a whole is accelerated. Another advantage is that in particular the carbons considered inferior, in view of their particularly high content of volatile matter, can be usefully used as carbonization accelerators and in which the upstream process steps for mixing different charges of carbon can be omitted. Another embodiment of this method is provided to introduce water vapor at all times in such a manner that the building materials of the coke oven are never exposed to a temperature higher than 1400 ° C. In practiceThis can be achieved, for example, by installing temperature measuring points in those places in the brickwork structure where more heat is expected to accumulate empirically and by providing opening ports to introduce water vapor into these areas as well. In an experimental model procedure, a heat recovery coke oven is provided with five opening ports that allow to introduce water vapor into the coking chamber. In addition, all combustion gas channels that connect the coking chamber to the brick hearth of the coke oven are also provided with ports of opening that allows water vapor to enter the brick hearth of the coke oven. The steam lines connected to a central main steam line and accommodating a measuring device as well as a control element each are found in all of these opening ports. The temperature measuring instruments were arranged in the roof of the coking chamber and in the main raw gas pipe that transports the raw gas from the brick hearth of the coke oven to the chimney. The measured temperature values were transmitted to a procedure computer that in turn activates the measurement devices. Loaded in this experimental procedure are the coal loads that have different elevated portions of slightly volatile constituents that in a conventional coke oven can lead to overheating and damage to the refractory material. This was managed to control the process and the coke oven at all times in such a way that any damage to the coke oven material or loss of valuable substances is avoided.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for the production of coke in a coking chamber of the "type without recovery" or the "type of heat recovery", wherein: the coking chamber is loaded with a bed of coal, the coal is heated and the constituents of Volatile carbon are volatilized from the charge of coal, these constituents of volatile coal are partially oxidized by means of supplied air (primary air), these constituents of volatile carbon and gases pass through the flue gas channels in the brick hearth of the coke oven, where these channels are arranged in the side walls of the coking chamber and the volatile, unburned carbon constituents are burned in the brick hearth of the coke oven, where both the coking chamber and the hearth Coke oven brick have facilities that restrict the air supply characterized because the temperature is measured, and water vapor is introduced for cooling ento, if required.

2. The method according to claim 1, further characterized in that the temperature is measured in the coking chamber, and water vapor is introduced into the gas space of the coking chamber for cooling, if required.

3. - The method according to claim 1, further characterized in that steam is introduced into the combustion gas channels for cooling the brick hearth of the coke oven, if required.

4. The method according to any of the preceding claims 1 to 3, further characterized in that the water vapor supply is controlled at all times in such a way that the maximum temperature at which the construction materials of the storage furnace are exposed. coke does not exceed 1400 ° C.

5. The method according to any of claims 1 to 4 above, further characterized in that the water vapor is introduced at a high pressure.

6. - The method according to any of claims 1 to 5 above, further characterized in that the water vapor has a temperature of 150 ° C to 300 ° C.

7. - The method according to any of claims 1 to 6 above, further characterized in that the water vapor is supplied as water vapor / air mixtures.

8. - A device for applying the method according to any of the preceding claims, characterized in that the inlet ports that allow introducing water vapor or water vapor / air mixture are provided in the wall of the coke oven or water channels. combustion gas.

9. - A device for applying the method according to any of the preceding claims, characterized in that the central vapor line leads to the coke ovens, where the ramifications of the central steam line lead to the opening ports.

10. - The device according to claim 5, further characterized in that the measuring device and the control element for varying the volume of combustion air required during the entire coking time are provided in the opening ports.