JP6102852B2 - Method for cleaning and recovering filler and apparatus therefor - Google Patents

Description

  The present invention relates to a method and an apparatus for cleaning and recovering a packing material which is extracted from a packing material packed in a hydrogen sulfide absorption tower, and is cleaned and recovered. The present invention relates to a method and an apparatus for cleaning and recovering a packing material that can extract, clean, and recover the packing material packed in a hydrogen absorption tower.

  Coke used in iron making or the like is produced by carbonizing coal. The gas produced as a by-product at that time is called coke oven gas, and has high utility value as a fuel because it contains hydrogen and methane as main components. In addition, digestion gas obtained by anaerobic microbial digestion (fermentation) of industrial wastewater containing organic matter and sewage sludge has methane as a main component and can also be used as fuel.

However, these gases contain hydrogen sulfide (H ₂ S) as an impurity derived from the raw materials, and if used as fuel, they cause corrosion of equipment and air pollution. Therefore, it is necessary to remove (desulfurize) hydrogen sulfide before using it as fuel.

As a desulfurization method, a wet desulfurization method in which a gas to be treated such as coke oven gas is brought into contact with an alkaline aqueous solution in a desulfurization tower (absorption tower) and hydrogen sulfide contained in the gas is absorbed into the aqueous solution is widely used (patent) References 1, 2). The alkaline aqueous solution is also called an absorbing solution, and an aqueous solution containing ammonia (NH ₄ OH), sodium carbonate (Na ₂ CO ₃ ), sodium hydroxide (NaOH) or the like as an alkali source is used.

In particular, when the gas to be treated is a coke oven gas, gaseous ammonia is contained in the coke oven gas itself, so the Takahax method and the Fmax method that absorb this into water and use it as the absorbent are generally adopted. Has been. When the absorption liquid is ammonia water, in the absorption tower, H ₂ S in the gas to be treated reacts with NH ₄ OH and is absorbed as ammonium hydrogen sulfide (NH ₄ SH) in the ammonia water.

  The actual hydrogen sulfide absorption treatment is performed by introducing the gas to be treated from below the absorption tower, spraying the absorbing liquid from the top of the absorption tower using a spray nozzle or the like, and bringing them into contact with each other. The desulfurized gas to be treated is extracted from the top of the absorption tower.

  At this time, by filling the inside of the hydrogen sulfide absorption tower with a filler such as a polypropylene resin or a molded product of polyethylene resin, efficient desulfurization with improved contact efficiency between the gas to be treated and the absorbing liquid is performed. It has been broken.

  However, when the absorption tower is operated for a long period of time, a part of the absorbed hydrogen sulfide is oxidized in the absorption tower to form sludge-like sulfur, which adheres to and accumulates on the filler. As a result, problems such as an increase in pressure loss in the absorption tower and a decrease in gas-liquid contact efficiency due to the occurrence of drift are caused. For this reason, it is necessary to periodically extract the packing material inside the absorption tower, clean it, refill it, or replace it with a new packing material.

  As a method of extracting and collecting the filler from the hydrogen sulfide absorption tower, a small belt conveyor is inserted into the absorption tower, the filler is placed on the conveyor by hand digging using a scoop, and the flexible container is passed through the chute. A method of accommodating in a container such as a bag is known.

JP 2013-234223 A Japanese Patent Laid-Open No. 2001-271074

However, the method for extracting the filler has the following problems.
1) A general hydrogen sulfide absorption tower is filled with a large amount of packing material on the scale of several hundreds of cubic meters. It is extremely hard to manually transfer this to a conveyor. Since ammonia, which is a component, remains, and the working environment is severe, the burden on the worker is excessive. 2) Since it is a work by human power, it is inefficient and it is necessary to stop the operation of the desulfurization apparatus for a long time. 3) Since the work is performed outdoors using a belt conveyor, it cannot be performed in bad weather.

  In addition, when the collected filler is reused, cleaning is performed, but even when it is discarded and replaced with a new one, the filler is attached with harmful substances such as sulfur. It cannot be discharged as industrial waste and must be cleaned. Cleaning of the filler is performed in a batch system in which the filler is immersed in a tank in which water is stored in a net-like container, and the operator swings up, down, left and right. This cleaning work is also a heavy burden in the collection work of the filler.

  In view of the above-described problems, the present invention eliminates manual work as much as possible, and safely and efficiently extracts, cleans, and recovers a filler filled in a hydrogen sulfide absorption tower, and an apparatus therefor The purpose is to provide.

That is, the gist of the present invention is as follows.
(1) A method for cleaning and recovering a filler by extracting a filler filled in a hydrogen sulfide absorption tower, and cleaning and collecting the duct using a duct connected to a first vacuum device via a cyclone separator. In the extraction step for extracting the filler from the hydrogen sulfide absorption tower, the collection step for collecting the filler extracted in the extraction step using the cyclonic separator, and the collection step. The mixing step of mixing the collected filler with a cleaning liquid, and the suction agent and the cleaning material mixed by the mixing step are sucked using a second vacuum device connected to a liquid cyclone for cleaning the filler. A cleaning process for introducing and cleaning the liquid cyclone type cleaning device, and the filler cleaned in the cleaning step is taken out from the liquid cyclone type cleaning device. Cleaning method for recovering the filler, characterized in that it comprises a recovery step of recovering, at least.

(2) A buffer tank is provided between the cyclonic separation device and the hydrocyclone cleaning device, and the mixing step is performed by introducing a filler and a cleaning liquid into the buffer tank. The method for cleaning and recovering a filler according to (1) above.

(3) The filler according to (1) or (2) above, wherein at least one inner surface of the duct, the cyclonic separator, and the liquid cyclonic cleaning device is coated with a fluororesin. Cleaning and recovery method.

(4) The method for cleaning and collecting a filler according to any one of (1) to (3), wherein at least a part of the duct is a flexible duct.

(5) A cleaning / recovery device for a filler that extracts, cleans, and recovers the filler filled in the hydrogen sulfide absorption tower, and includes a duct for extracting the filler from the hydrogen sulfide absorption tower, and the duct. A cleaning liquid is supplied to and mixed with the cyclone type separator connected to collect the filler, the first vacuum device connected to the cyclone separator, and the filler collected by the cyclone separator. And a second cyclone device connected to the hydrocyclone cleaning device, and at least a mixing cyclone cleaning device connected to the mixing device and a second cyclone cleaning device connected to the hydrocyclone cleaning device .

  According to the present invention, the filler filled in the hydrogen sulfide absorption tower can be extracted, cleaned, and recovered safely and efficiently, with little manual work as in the prior art. Further, according to the present invention, the filler can be extracted in a short time, and its implementation is not affected by the weather, so that the influence on the entire plant using the desulfurization equipment is minimized. Can do.

It is the schematic of the washing | cleaning collection | recovery apparatus of a filler.

Next, an embodiment of the method for cleaning and collecting a filler according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of an apparatus for carrying out the filler cleaning and recovery method of the present invention. In the figure, reference numeral 1 denotes a hydrogen sulfide absorption tower, which is filled with a filler 2 for promoting gas-liquid contact. As the filler 2, an irregular filler made of resin such as polypropylene or polypropylene can be used. The packing material 2 is packed so as to form a layer on a plurality of supports (not shown) installed in the absorption tower, and this layer is called a packed bed.

  In the desulfurization treatment, a gas to be treated such as coke oven gas is introduced from below the absorption tower 1, and an absorbing liquid is sprayed from the top of the absorption tower using a spray nozzle (not shown), and both are brought into contact with each other. To be done. There are various methods for wet desulfurization treatment using an absorption tower in which the types of alkali sources and catalysts contained in the absorption liquid to be used are different. The method and apparatus for cleaning and recovering a filler of the present invention uses a filler. Anything can be applied.

  When the absorption tower is operated for a long period of time, sludge-like sulfur or the like adheres to and accumulates on the filler, so that it is necessary to remove the filler once and wash it or replace it with a new filler. The timing for cleaning or replacing the packing material varies depending on the type of packing material to be used, the composition of the gas to be treated, the operating condition of the apparatus, etc., but it is preferable to perform it when the pressure loss in the absorption tower exceeds a certain level.

-Extraction process In order to clean and collect the packing material, it is necessary to first extract the packing material from the inside of the absorption tower. The packing material is extracted by inserting the duct 4 through the opening 3 provided on the side surface of the absorption tower. A first vacuum device 6 is connected to the duct 4 via a cyclonic separator 5.

  As the first vacuum device 6, various known devices such as a vacuum pump (vacuum pump) and a vacuum damper (vacuum car) can be used as long as they have an ability to suck the filler through the duct 4. It is preferable to use a vacuum damper because it has a suction force and is easy to move.

  When extracting, the 1st vacuum apparatus 6 is drive | operated and a filler is attracted | sucked from the front-end | tip of the duct 4 inserted in the packed tower. At this time, it is preferable that at least a part of the duct 4 is bendable, and a flexible duct such as a bellows duct is particularly preferable in order to suck the filler in the packed tower without leaving any corners. Further, by using a duct that can be bent, the duct can be prevented from being blocked by the filler.

  As shown in FIG. 1, when a plurality of packed beds are provided in the packed tower, the extraction operation is sequentially performed on each packed bed. When the total amount of packing material is small, it is possible to extract all the packing material at once and perform the subsequent processing, but the capacity of the general packed tower is the capacity of the equipment used for the subsequent processing. Therefore, in such a case, a series of processing from extraction to collection is performed in a plurality of times.

-Collecting process The filler 3 extracted through the duct 4 is collected by a cyclone separator 5 provided between the duct 4 and the first vacuum device 6. The filler 3 sucked together with the air from the duct 4 is separated from the air by the centrifugal force inside the cyclonic separator 5 and the filler is collected in the lower part of the cyclone, while the air is collected from the outlet at the upper part of the cyclone. Then, the air is exhausted to the first vacuum device 6.

  As the cyclonic separator 5, a general gas cyclone can be used. It is preferable that a lower portion of the cyclonic separator 5 is provided with a filler accumulation unit (not shown) that is a space for temporarily accumulating the collected filler.

  The lower part of the cyclonic separator 5 is connected to an apparatus for carrying out a mixing step described later by a pipe provided with a valve 7. During the extraction process and the collection process, the valve 7 needs to be closed in order to maintain the reduced pressure state by the first vacuum device 6. The kind of all the valves used in the present invention including the valve 7 is not particularly limited, but a general rotary valve can be used.

-Mixing process Next, the mixing process which mixes the filler 2 collected in the said collection process and a washing | cleaning liquid is implemented. The method for mixing the filler and the cleaning liquid is not particularly limited, and can be performed by supplying the cleaning liquid to the filler at an arbitrary timing until the process proceeds to the next cleaning step. In the example shown in FIG. 1, a buffer tank 9 to which a cleaning liquid tank 8 is connected is provided below the cyclone separator 5, and mixing is performed in the buffer tank 9.

The procedure for actually carrying out the mixing step is as follows.
First, when a certain amount of filler is collected in the collecting step, the operation of the first vacuum device 6 is stopped, the valve 7 is opened, and the collected filler 2 is transferred to the buffer tank 9. The cleaning liquid is stored in the cleaning liquid tank 8 and is supplied to the buffer tank 9 by opening a valve 10 provided between the cleaning liquid tank 8 and the buffer tank 9. Either the filler or the cleaning liquid may be supplied to the buffer tank 9 first or simultaneously. In addition, as shown in FIG. 1, the buffer tank 9 is installed below both the cyclone separator 5 and the cleaning liquid tank 8 so that the filler and the cleaning liquid can be removed from the buffer tank using its own weight by simply opening the valve. 9 can be moved.

  A pipe for connecting to an apparatus used in a cleaning process to be described later is provided below the buffer tank 9. A valve 11 is provided in the pipe, and the valve 11 is closed while the mixing step is performed.

-Cleaning liquid The composition and temperature of the cleaning liquid to be used are not particularly limited, and may be determined according to the type of dirt adhering to the filler and the influence of deterioration (dissolution, corrosion, etc.) on the filler. Specifically, what added the anionic, cationic, or amphoteric surfactant as a washing | cleaning agent to the warm water as a solvent can use it conveniently. The concentration of the cleaning agent contained in the cleaning liquid is preferably 0.1 to 5% by mass. Further, water or an organic solvent alone may be used.

  The balance between the amount of the cleaning liquid and the filler mixed in the mixing step is not particularly limited, but the amount of the filler becomes a slurry, can be smoothly transferred to the apparatus used in the next cleaning step, and can be appropriately cleaned. And it is sufficient.

-Cleaning step Next, the valve 11 is opened, and the filler and the cleaning liquid in a slurry state are transferred to the hydrocyclone cleaning device 12 through a pipe provided below the buffer tank 9. In general, a liquid cyclone is an apparatus used for separation, classification, concentration and the like of solids contained in a liquid. In the present invention, this is used for cleaning and recovery of a filler. The filler and the cleaning liquid introduced into the liquid cyclone cleaning device 12 are vigorously stirred by the spiral flow generated inside the cyclone, and as a result, are cleaned in a short time. The cleaned filler is accumulated below the hydrocyclone cleaning device 12 by the action of centrifugal force.

  As the liquid cyclone cleaning device 12, a general liquid cyclone can be used. Similarly to the cyclone type separation device 5 described above, the hydrocyclone type cleaning device 12 is also provided with a filler accumulation unit (not shown), which is a space for temporarily accumulating the filler, in the lower part thereof. Is preferred. In addition, a valve 13 is connected to the lower part of the hydrocyclone cleaning device 12, and the cleaning process using the liquid cyclone cleaning device 12 is performed with the valve 13 closed.

  In the present invention, it is important to transfer the filler and the cleaning liquid in a mixed state to the hydrocyclone cleaning device 12 using the second vacuum device 14 connected to the upper outlet of the liquid cyclone cleaning device 12. is there. In general, liquid feeding to the liquid cyclone is performed using a centrifugal pump or the like installed upstream of the cyclone, but in the present invention, suction is performed by a vacuum device installed downstream of the cyclone. According to this method, since the filler does not pass through the pump, the filler of any material, shape, and size can be reliably transferred, and the filler is damaged by the impeller of the pump or the like. There is nothing.

-Recovery process Finally, the filler cleaned in the cleaning process is taken out from the liquid cyclone cleaning apparatus 12 and recovered. The collection is performed by installing a collection container 15 below the hydrocyclone cleaning device 12 and opening the valve 13 in a state where the operation of the second vacuum device 14 is stopped. At this time, since the cleaning liquid is discharged together with the filler from the liquid cyclone cleaning apparatus 12, a solid-liquid separation means (illustrated) for separating the filler and the cleaning liquid between the liquid cyclone cleaning apparatus 12 and the recovery container 15. Is not provided). As the solid-liquid separation means, it is preferable to use a mesh, a grid, a punching plate, or the like that allows the cleaning liquid to pass therethrough but does not allow the filler to pass therethrough, and it is more preferable to use a chute of those forms.

  The recovery container 15 can be used regardless of the type as long as it has strength and capacity to accommodate the filler. For example, a collection transport vehicle such as a flexible container bag, a drum can, or a dump truck can be used as the collection container 15, and it is preferable to use a flexible container bag from the viewpoint of ease of handling and cost.

  The collected packing material has already removed harmful sulfur and other deposits by washing, so it can be disposed of as waste as it is, and can also be reused by filling it into a hydrogen sulfide absorption tower. It is.

-Treatment of used cleaning liquid In the above-described cleaning process, the cleaning liquid is discharged from the upper outlet of the hydrocyclone cleaning apparatus 12. Also in the recovery step, the cleaning liquid is discharged from the lower part of the hydrocyclone cleaning device 12. Since these used cleaning liquids contain contaminants such as sulfur sludge separated from the filler, they are disposed of after waste liquid treatment. Various known methods can be used for the waste liquid treatment. The solid sulfur finally obtained by solid-liquid separation is preferably combusted and disposed of from the viewpoint of processing costs.

-Coating of inner surface of apparatus In the present invention, it is preferable that at least one inner surface of the duct 4, the cyclonic separator 5 and the liquid cyclonic cleaning device 12 is coated with a fluororesin, and all the inner surfaces thereof are coated. More preferably, it is coated with a fluororesin. In addition to being excellent in corrosion resistance and chemical resistance, fluororesin is non-adhesive and has low friction. Therefore, coating the fluororesin on the inner surface of the device allows the filler and dirt to adhere to the inner wall surface of the device. This prevents the device from being blocked.

  Examples of the fluororesin include various known tetrafluoroethylene / hexafluoropropylene copolymers (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymers (PFA), and tetrafluoroethylene (PTFE). Although it can be used, it is preferable to use FEP having the lowest critical surface tension among fluororesins and excellent in non-adhesiveness.

  According to the method of the present invention, since it is not necessary to carry out and carry out the cleaning of the packing material by human power as has been done conventionally, the packing material packed in the hydrogen sulfide absorption tower is extracted safely and efficiently, Can be washed and recovered. Moreover, since it can wash | clean continuously using a liquid cyclone type washing | cleaning apparatus, compared with the batch type washing | cleaning by the conventional manual labor, a process can be completed in a very short time. The method and apparatus of the present invention are particularly useful for cleaning and recovering a filler of a hydrogen sulfide absorption tower used for desulfurization of coke oven gas in a steelworks or the like.

1: Hydrogen sulfide absorption tower 2: Packing material 3: Opening portion 4: Duct 5: Cyclone-type separation device 6: First vacuum device 7: Valve 8: Cleaning liquid tank 9: Buffer tank 10: Valve 11: Valve 12: Liquid cyclone Type cleaning device 13: valve 14: second vacuum device 15: collection container

Claims (5)

A method for cleaning and recovering a filler by extracting, cleaning, and recovering a filler filled in a hydrogen sulfide absorption tower,
An extraction step of extracting the filler from the hydrogen sulfide absorption tower by suction using a duct connected to the first vacuum device via a cyclonic separator;
A collecting step of collecting the filler extracted in the extraction step using the cyclonic separator;
A mixing step of mixing the filler collected in the collecting step with a cleaning liquid;
A cleaning step of introducing and cleaning the filler and the cleaning liquid mixed in the mixing step into the liquid cyclone type cleaning device by sucking using a second vacuum device connected to the liquid cyclone for cleaning the filler,
A recovery step of taking out and recovering the filler that has been cleaned in the cleaning step, from the hydrocyclone cleaning device;
A method for cleaning and recovering a filler, comprising: A buffer tank is provided between the cyclonic separator and the liquid cyclonic cleaning device,
The method for cleaning and recovering a filler according to claim 1, wherein the mixing step is performed by introducing a filler and a cleaning liquid into the buffer tank.   The method for cleaning and recovering a filling material according to claim 1 or 2, wherein at least one inner surface of the duct, the cyclonic separator, and the hydrocyclone cleaner is coated with a fluororesin.   The method for cleaning and collecting a filler according to any one of claims 1 to 3, wherein at least a part of the duct is a flexible duct. A cleaning / recovery device for a filler that extracts, cleans, and recovers the filler filled in the hydrogen sulfide absorption tower,
A duct for extracting the filler from the hydrogen sulfide absorption tower;
A cyclonic separation device connected to the duct for collecting filler;
A first vacuum device connected to the cyclonic separator;
A mixing device for supplying and mixing the cleaning liquid to the filler collected by the cyclonic separator;
A hydrocyclone cleaning device connected to the mixing device;
A filling material cleaning and recovering device comprising at least a second vacuum device connected to the hydrocyclone cleaning device.

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