JP2012246350A - Manufacturing system of hydrogen-enriched coke oven gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably manufacture a hydrogen-enriched coke oven gas containing hydrogen in a high concentration by bleeding a high-temperature coke oven gas from a coke oven kiln and utilizing the sensible heat.SOLUTION: The manufacturing system of hydrogen-enriched coke oven gas is configured such that a coke oven gas is circulated from a coke oven to a crude coke oven gas reforming apparatus by connecting a bleeding pipe connected to the coke oven and the crude coke oven gas reforming apparatus; a control system is provided which control the flow of a crude coke oven gas circulated from the coke oven to the crude coke oven gas reforming apparatus in response to the fluctuation in the pressure and the flow volume of the coke oven gas generated in the coke oven; and at least, a metal oxide catalyst selected from a steam reforming catalyst, a carbon dioxide reforming catalyst, a partial oxidation reforming catalyst and a shift catalyst is packed in the crude coke oven gas reforming apparatus.

Description

  The present invention relates to an apparatus for producing a hydrogen-enriched coke oven gas containing a high concentration of hydrogen from a high-temperature crude coke oven gas generated from a coke oven.

  In a steelmaking coke oven, coke oven gas (COG) generated during the dry distillation of coal is recovered by a collecting pipe called a dry main and used for various fuels in the steelworks. At this time, since the raw coke oven gas immediately after generation is at a high temperature of about 900 ° C., in principle, the energy recovery can be performed by recovering the sensible heat of the gas or reforming the gas using the high temperature. Various approaches have been made in the past. For example, Patent Documents 1 and 2 disclose a COG sensible heat recovery apparatus. Patent Document 3 discloses a high-temperature COG gas reforming apparatus. Since coke ovens perform batch carbonization of individual coke ovens, in general, a large amount of hydrocarbon components, mainly volatile components, are generated in the initial pyrolysis, followed by secondary heat. It is known that the decomposition proceeds and a heavy hydrocarbon component mainly composed of condensed polycyclic aromatics is generated, but the generation amount gradually decreases. In addition, a non-steady COG generation pattern in which the COG components change greatly with this change. Under these circumstances, there is no effective method to efficiently utilize the thermal energy of unsteady crude coke oven gas while maintaining high sensible heat, and this is a problem in promoting further energy saving in the blast furnace integrated steelmaking process. there were.

On the other hand, Patent Documents 4 and 5 relate to a technique for obtaining a reformed gas containing hydrogen at a high concentration from light hydrocarbons or heavy hydrocarbons such as tar contained in the gas for high-temperature crude coke oven gas. As described in (1), a reforming method is disclosed in which oxygen or water vapor is blown to react in a high temperature range exceeding 1200 ° C. However, since the reforming reaction proceeds in an ultra-high temperature region, the heat treatment apparatus becomes very expensive due to the heat resistance of the apparatus, resulting in a high construction cost, and a large amount of utility such as oxygen and steam introduced from the outside is required. Therefore, there are problems such as high operating costs and a large amount of CO ₂ generated due to the progress of the combustion reaction.

Japanese Patent Publication No.59-44346 JP 58-76487 A JP 2003-55671 A JP 2001-220484 A JP 2002-155288 A

  When performing gas reforming treatment by extracting tar-associated crude COG from a coke oven, the extracted COG is cooled with ammonia water to allow a large amount of tar to condense, or there is a large gap when the extraction pipe is closed. The only choice was whether to apply a damper to allow gas backflow. For this reason, the COG extracted from the coke oven is thermally low in temperature and poor in reactivity, and the hot treatment of coke oven gas at 700 ° C or higher is extremely limited and has been practically used. There wasn't.

  Therefore, the present invention supplies the tar-associated crude COG to a crude coke oven gas reforming apparatus while maintaining high reactivity at a high temperature, and uses a catalyst to enrich hydrogen at a relatively low temperature of about 800 ° C. An object is to provide an inexpensive and safe system for producing coke oven gas.

As a result of intensive studies by the inventor, the inventors have invented the following means for solving the above problems.
(1) Using the heat retained in the high-temperature crude coke oven gas extracted from the coke oven for catalytic reaction, the crude coke oven gas is reformed into a coke oven gas containing a higher concentration of hydrogen. Coke oven gas production system,
A coke oven,
A bleed pipe connected to the coke oven;
A crude coke oven gas reforming apparatus connected to the extraction pipe;
A control system for controlling the flow of the crude coke oven gas flowing from the coke oven to the crude coke oven gas reforming treatment apparatus in response to fluctuations in the pressure and flow rate of the coke oven gas generated from the coke oven;
And circulating the coke oven gas from the coke oven to the crude coke oven gas reforming apparatus by the extraction pipe,
2. The hydrogen-enriched coke oven gas production system, wherein the crude coke oven gas reforming apparatus comprises a catalyst.

  (2) The hydrogen enrichment according to (1), wherein the light hydrocarbon component in the crude coke oven gas and the heavy hydrocarbon component accompanying the crude coke oven gas are reformed by the catalyst. Coke oven gas production system.

(3) The catalyst is composed of at least one selected from the group consisting of a steam reforming catalyst, a carbon dioxide reforming catalyst, a partial oxidation reforming catalyst, and a shift catalyst (1) or (2) The hydrogen-enriched coke oven gas production system described in 1.
(4) The hydrogen-enriched coke oven gas production system according to any one of (1) to (3), wherein the extraction pipe is equipped with a heater, and the crude coke oven gas is maintained at 600 ° C. or higher. .
(5) A bleeder valve for preventing an abnormal increase in pressure in the crude coke oven gas reforming apparatus is provided in the middle of the extraction pipe. (1) to (4) The hydrogen-enriched coke oven gas production system according to any one of the above.
(6) An on-off valve, a blower, a bypass valve for controlling fluctuations in the flow rate of the crude coke oven gas flowing into the crude coke oven gas reforming apparatus in the middle of the extraction pipe, and a control device for controlling them. The hydrogen-enriched coke oven gas production system according to any one of (1) to (5), which is provided.
(7) The hydrogen-enriched coke oven gas production system according to any one of (1) to (6), wherein the coke oven kiln is connected to a dry main through a water seal valve.
(8) The heater-extracted bleed pipe has an on-off valve, has an inner diameter of 80 mm or more, and an outer diameter of less than 1 m, according to any one of (1) to (7) Hydrogen enriched coke oven gas production system.
(9) The hydrogen enriched coke oven gas production system according to (8), wherein the extraction pipe with heater further has an emergency shutoff valve.
(10) A cooling device that is connected to the crude coke oven gas reforming treatment device and cools the hydrogen-enriched coke oven gas treated by the crude coke oven gas reforming treatment device, and a cooled hydrogen-enriched coke oven The hydrogen-enriched coke oven gas production system according to any one of (1) to (9), comprising a hydrogen-enriched coke oven gas storage device for storing gas.

The features of the present invention will be described.
First, a crude coke oven gas reforming apparatus equipped with a catalyst for converting hydrocarbons in the crude coke oven gas into hydrogen is directly arranged with a bleed pipe from the coke oven, thereby generating a coarse coke oven. COG can be supplied to a coke gas processing device while maintaining a high temperature, and a production system that enables production of hydrogen-enriched coke oven gas is constructed. As a result, effective utilization of sensible heat of crude COG Is possible. As described above, in the prior art, it is difficult to achieve both effective use of sensible heat of crude COG and production of hydrogen-enriched coke oven gas, and hot treatment of crude COG has not been realized.

  Next, in the present invention, the light hydrocarbon component contained in the crude COG and the catalyst for converting the heavy hydrocarbon component accompanying the crude COG into hydrogen are used in the crude coke oven gas reforming apparatus. By using at least one selected from the group consisting of a steam reforming catalyst, a carbon dioxide reforming catalyst, a partial oxidation reforming catalyst, and a shift catalyst as the catalyst, the above catalytic reaction was made possible.

  The present invention makes it possible to stably produce a hydrogen-enriched coke oven gas containing a high concentration of hydrogen from high-temperature crude COG.

It is a schematic diagram of the high temperature coke oven gas processing apparatus in the embodiment of the present invention.

  Effectively uses the sensible heat of about 900 ° C held by the high-temperature crude coke oven gas generated from the coke oven, and stably uses a tar-containing gas whose pressure and flow rate change over time, such as hydrogen, carbon monoxide, etc. If it can be converted into fuel components such as light hydrocarbons, not only will it lead to energy amplification, but the reducing gas volume produced there will be greatly amplified so that it can be applied to, for example, iron ore to produce reduced iron If the process becomes possible, the carbon dioxide emissions generated in the blast furnace process that currently reduces iron ore with coke may be significantly reduced. Hereinafter, embodiments for carrying out the present invention will be described in detail.

<Device configuration>
An embodiment of the present invention will be described with reference to FIG. A conventional coke oven furnace 1 shown in FIG. 1 is provided with a bleed pipe 2 with heater, an on-off valve 3 and an emergency shut-off valve 4 and supplied to a crude coke oven gas reforming apparatus 5 connected thereto. The crude coke oven gas reforming treatment apparatus 5 is housed in a heating furnace 6 and maintains the furnace temperature at 600 ° C. or higher, more preferably 800 ° C. or higher during COG reforming, and tar in the piping system. Prevent condensation. A bleeder valve 7 is provided in the middle of the bleed pipe 2 with a heater, and when the pressure on the inlet side of the on-off valve 3 temporarily rises, the abnormal pressure rise in the system is prevented by opening the bleeder valve 7. The hydrogen-enriched coke oven gas treated by the crude coke oven gas reforming treatment device 5 is appropriately cooled by the cooling device 8 and supplied to the hydrogen-enriched coke oven gas storage device 11. When the ventilation resistance in the crude coke oven gas reforming apparatus 5 is large, the required flow rate may be secured by sucking the cooled COG with the blower 9. However, when the resistance rises to near the blower capacity limit, the blower is branched by opening the bypass valve 10 to flow to the hydrogen-rich coke oven gas storage device. Moreover, since COG cooled to about room temperature by the cooling device 8 is dry from which tar content has been removed, a commercially available general blower, valve, or the like can be used for the operation. A commercially available scrubber etc. can be used for a cooling device. In addition, when there is a risk of clogging with dust in the COG, a dust collector such as a cyclone may be provided in the middle of the pipeline system.
In order to control fluctuations in the pressure and flow rate of the crude coke oven gas flowing into the coarse coke oven gas reformer 5 in the middle of the bleed pipe 2 from the coke oven, an on-off valve 3, an emergency shut-off valve 4, a crude coke oven gas The reformer 5, the blower 9, the bypass valve 10 and the like are controlled by the control device 15.

<Flow of COG>
In FIG. 1, in the case of COG under suitable conditions in the coke oven furnace 1, the open / close valve 3 of the extraction pipe 2 with heater is opened, and wet COG is supplied from the coke oven furnace 1 to the crude coke oven gas reforming treatment device 5. Is done. Here, COG under suitable conditions is a state where at least the pressure on the side of the extraction pipe 2 with heater is not larger than the pressure on the side of the coke oven kiln. In the state where the on-off valve 3 is opened, the water seal valve 12 of the coke oven kiln may be opened or closed. Here, when the water seal valve 12 is opened, it is preferable that the pressure adjusting mechanism or the like of the spray device 13 is operated so that COG flows from the coke oven furnace 1 to the dry main 14.

  In the state where the on-off valve 3 is opened and the water seal valve 12 is closed, as long as COG continues to be generated in the coke oven kiln 1, all the COG generated in the coke oven kiln 1 is the extraction tube 2 with a heater. Therefore, no back flow occurs on average over a long period of time. That is, on average, the difference in pressure between the coke oven kiln and the extraction tube defined by ([pressure in the coke oven kiln] − [pressure in the extraction tube with heater]) is positive, and this pressure difference is the same as that in the coke oven kiln. The value is proportional to the amount of COG generated. However, instantaneously, the COG generation rate in the coke oven furnace 1 is not constant, and fluctuates even in a short time. For example, the fluctuation factor is that the coal in the coke oven furnace 1 undergoes primary pyrolysis and then undergoes secondary pyrolysis. Since it is not uniform with respect to the elapsed time later, it is conceivable that the amount of COG generated in the coke oven furnace 1 suddenly increases, and the pressure in the extraction pipe 2 rapidly increases accordingly. In such a case, the bleeder valve 7 is automatically opened and the generated COG is discharged from the extraction pipe 2 to cope with it.

  However, since the wet COG is passed through the pipe, when the pressure in the bleed pipe 2 is rapidly increased due to clogging or sticking due to tar or the like, or when the control device 15 becomes a serious failure, It is necessary to stop COG bleed. In that case, it is necessary to close the emergency shut-off valve 4 so as to cut off the coke oven kiln and the crude coke oven gas reforming apparatus so as not to hinder the operation of the coke oven kiln. is there.

<Rough coke oven gas reformer>
For example, a COG reforming apparatus disclosed in Patent Document 3 can be applied to the crude coke oven gas reforming apparatus 6. A catalyst filling tank filled with at least one metal oxide catalyst selected from the group consisting of a steam reforming catalyst, a carbon dioxide reforming catalyst, a partial oxidation reforming catalyst, and a shift catalyst is disposed inside the apparatus. However, it is necessary to use a catalyst filling tank that does not cause a pressure loss even if the crude coke oven gas is supplied to the apparatus. In addition, since this apparatus is heated to a temperature of about 600 ° C. or more and 900 ° C. or less, it is necessary to manufacture a material and a structure that can withstand the temperature of the apparatus and the catalyst filling tank. As the material, for example, a heat resistant stainless steel such as SUS310S, a heat resistant nickel alloy, or a heat resistant ceramic can be suitably used.

<Bleeding tube with heater>
Although the extraction pipe 2 with a heater is directly connected to the coke oven furnace 1, a pipe made of heat-resistant stainless steel such as SUS310S, heat-resistant nickel alloy, or heat-resistant ceramic can be used. . The bleed pipe 2 with a heater has a heater to prevent the temperature of the bleed COG from dropping below the reforming temperature, and the temperature of the bleed COG in the bleed pipe 2 with heater can be maintained at 600 ° C. or higher. Desirably, it is more desirable to maintain at 700 ° C. or higher. In the hydrogen-enriched coke oven gas production system of the present invention, the extracted COG is normally kept at 700 ° C. or higher, so that tar condensation is difficult to occur, but carbon deposition due to high temperature COG pyrolysis on the inner surface of the pipe is inevitable. For this reason, from the viewpoint of prevention of blockage, the inner diameter of the extraction tube 2 with heater is preferably 80 mm or more. Moreover, since it becomes impossible to install piping between kilns in a coke oven when the piping diameter is excessive, it is preferable that the outer diameter of the extraction pipe 2 with a heater is an average interval between kilns, for example, less than 1 m.

<Open / close valve>
The on-off valve 3 may have any type as long as it can withstand a high temperature of 600 ° C. or higher, more preferably 800 ° C. or higher in the heating furnace, and the operation is not hindered by carbon deposition due to coking or dust biting. However, for example, a heat-resistant ball valve or a heat-resistant needle valve can be suitably used.

<Emergency shut-off valve>
As shown above, the emergency shut-off valve 4 operates the coke oven kiln 1 and the crude coke oven gas reforming when it deviates from the steady state and interferes with the operation of the coke oven kiln. The processing apparatus 5 is cut off. Any type can be used as long as it can withstand a high temperature of about 800 ° C. and the operation is not hindered by the precipitation of carbon due to caulking or the entrapment of dust. For example, a sand hopper or the like can be used. It can be suitably used.

<Heating furnace>
A commercially available electric furnace or combustion furnace can be used for the heating furnace 6.
The heating furnace 6 may house all of the above-described machine elements to be heated in one heating furnace, or independently for each of the extraction pipe 2 with heater, the emergency shut-off valve 4, and the crude coke oven gas reforming apparatus 5. A heating furnace may be provided.

<Material of structural material>
Any equipment can be used as long as it has the required strength, rigidity, durability, and sulfur corrosion resistance in an environment from room temperature to a high temperature of about 900 ° C. it can. For example, when using deformable parts, heat resistant stainless steel such as SUS310S, or metal such as heat resistant nickel alloy such as Inconel or Hastelloy, etc., in addition to the above materials, silica, alumina General heat-resistant ceramics such as can be used. In addition, when using a material with low oxidation resistance, these materials can be applied by maintaining the inside of the furnace in a non-oxidizing atmosphere, for example, a nitrogen atmosphere.

<Cooling device>
The cooling device 8 is not particularly limited as long as the gas can be efficiently cooled, but, for example, a scrubber type device that flushes and cools cooling water at around room temperature so as to counter flow with the high-temperature gas is preferably used. can do. In this cooling device, it is more preferable to install a circulation pump for circulating and reusing the cooling water from the viewpoint of efficient use of the cooling water.

<Catalyst>
Catalysts used for producing hydrogen-enriched coke oven gas from crude coke oven gas include hydrocarbon steam reforming reaction, carbon dioxide reforming reaction, Ni-based catalyst used in partial oxidation reforming reaction, Co-based catalyst, A noble metal catalyst such as Ru can be preferably used, but is not particularly limited thereto. Moreover, although an iron oxide catalyst, a copper oxide catalyst, or the like used for the shift reaction (carbon monoxide conversion reaction) can be suitably used, it is not particularly limited thereto. Furthermore, the catalyst used here may be a powder or a molded body. In the case of powder, the particle size and surface area are preferably adjusted, and in the case of a molded body, the pore volume, pore diameter, shape, etc. are suitably adjusted in consideration of the surface area and strength. The shape of the molded body may be any of spherical, cylindrical, ring-shaped, wheel-shaped, tablet-shaped, pellet-shaped, flake-shaped, granular, and the like, and further, a metal or ceramic honeycomb substrate coated with a catalyst component, etc. But you can.

  Here, it is preferable to reduce the catalyst before use. However, since a large amount of hydrogen is contained in the crude coke oven gas, the reduction proceeds during the reaction. However, especially when the catalyst requires a reduction treatment before the reaction, the reducing conditions are not particularly limited as long as the reducing conditions are set to a relatively high temperature and a reducing atmosphere. For example, hydrogen, carbon monoxide It may be in a gas atmosphere containing at least one of methane, in a gas atmosphere in which water vapor is mixed with these reducing gases, or in an atmosphere in which an inert gas such as nitrogen is mixed in these gases. In addition, the reduction temperature is preferably 500 ° C. to 1000 ° C., for example, and the reduction time depends on the amount of catalyst to be charged, and is preferably 30 minutes to 8 hours, for example. It may be a necessary time, and is not particularly limited to this condition.

The catalyst reactor is preferably a fluidized bed type or moving bed type when the catalyst is a powder, and a fixed bed type or moving bed type when the catalyst is a molded body. The inlet temperature of the catalyst layer is preferably used. As, it is preferable that it is 600-1100 degreeC. When the outlet temperature of the catalyst layer is lower than 600 ° C., the catalytic activity is hardly exhibited and the target hydrogen-enriched gas cannot be obtained, which is not preferable. On the other hand, when the inlet temperature of the catalyst layer exceeds 1100 ° C., it is economically disadvantageous because the reformer becomes expensive, for example, a heat-resistant structure of the reactor is required. The inlet temperature of the catalyst layer is more preferably 600 to 1000 ° C.
According to such a high-temperature coke oven gas treatment apparatus that is an embodiment of the present invention, since it has a control device that can cope with fluctuations in pressure and flow rate of coke oven gas generated from the coke oven, The coke oven gas can be produced stably.

DESCRIPTION OF SYMBOLS 1 Coke oven kiln 2 Extraction pipe with heater 3 On-off valve 4 Emergency shut-off valve 5 Coarse coke oven gas reforming treatment device 6 Heating furnace 7 Breeder valve 8 Cooling device 9 Blower 10 Bypass valve 11 Hydrogen-enriched coke oven gas storage device 12 Water Seal valve 13 Spray device 14 Dry main 15 Control device

Claims (10)

Coke oven gas for reforming crude coke oven gas into coke oven gas containing higher concentration of hydrogen by utilizing the heat held by the gas at the time of extraction from the high temperature crude coke oven gas extracted from the coke oven for the catalytic reaction A manufacturing system,
A coke oven,
A bleed pipe connected to the coke oven;
A crude coke oven gas reforming apparatus connected to the extraction pipe;
A control system for controlling the flow of the crude coke oven gas flowing from the coke oven to the crude coke oven gas reforming treatment apparatus in response to fluctuations in the pressure and flow rate of the coke oven gas generated from the coke oven;
And circulating the coke oven gas from the coke oven to the crude coke oven gas reforming apparatus by the extraction pipe,
2. The hydrogen-enriched coke oven gas production system, wherein the crude coke oven gas reforming apparatus comprises a catalyst.   2. The hydrogen-enriched coke oven gas according to claim 1, wherein the light hydrocarbon component in the crude coke oven gas and the heavy hydrocarbon component accompanying the crude coke oven gas are reformed by the catalyst. Manufacturing system.   3. The hydrogen-rich product according to claim 1, wherein the catalyst is at least one selected from the group consisting of a steam reforming catalyst, a carbon dioxide reforming catalyst, a partial oxidation reforming catalyst, and a shift catalyst. Coke oven gas production system.   The hydrogen-rich coke oven gas production system according to any one of claims 1 to 3, wherein the extraction pipe is equipped with a heater, and the crude coke oven gas is maintained at 600 ° C or higher.   The bleeder valve for preventing the abnormal rise of the pressure in the said rough coke oven gas reforming processing apparatus is provided in the middle of the said extraction pipe | tube, The any one of Claims 1-4 characterized by the above-mentioned. The hydrogen-enriched coke oven gas production system as described.   An on-off valve, a blower, a bypass valve for controlling fluctuations in the flow rate of the crude coke oven gas flowing into the crude coke oven gas reforming apparatus, and a controller for controlling them are provided in the middle of the extraction pipe. The hydrogen-enriched coke oven gas production system according to any one of claims 1 to 5.   The hydrogen-enriched coke oven gas production system according to any one of claims 1 to 6, wherein the coke oven furnace is connected to a dry main through a water seal valve.   The hydrogen-enriched coke oven according to any one of claims 1 to 7, wherein the extraction pipe with a heater has an on-off valve, an inner diameter is 80 mm or more, and an outer diameter is less than 1 m. Gas production system.   The hydrogen-rich coke oven gas production system according to claim 8, wherein the extraction pipe with heater further has an emergency shut-off valve.   A cooling device that is connected to the crude coke oven gas reformer and cools the hydrogen-enriched coke oven gas treated by the crude coke oven gas reformer, and stores the cooled hydrogen-enriched coke oven gas A hydrogen-enriched coke oven gas production system according to any one of claims 1 to 9, further comprising a hydrogen-enriched coke oven gas storage device.

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