JP2008094966A - Equipment and method for recovery of dust caught by dust collector of coke dry quenching facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide equipment and a method for recovery of dust caught by a dust collector of a coke dry quenching facility, capable of recovering the dust as a dry collected powder in a low-temperature state by lowering the temperature of the dust caught by the dust collector of the coke dry quenching facility. <P>SOLUTION: The equipment for recovery of the dust caught by the dust collector of the coke dry quenching facility is installed below the dust collector that catches the dust contained in waste gas exhausted from a cooling tower for cooling red-heated coke in the coke dry quenching facility. The equipment used for recovery of the dust has a dust collector powder exhaust pipe 10 for exhausting the dust collected by the dust collector, a cooling device 11 for cooling the peripheral surface of the dust collector powder exhaust pipe and a gas feed pipe 44 that feeds a stirring gas to the dust collector powder exhaust pipe for stirring the dust. Preferably, the length of the gas feed pipe corresponds to 40-60% of the length of the dust collector powder exhaust pipe. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to dust collection in a dust remover of high-temperature dust contained in waste gas generated in a coke dry fire extinguishing facility, and relates to a collection facility and a collection method for dust collected by the dust remover.

  The coke dry fire extinguishing equipment is a heat exchange system that obtains steam by an exhaust heat boiler while cooling red hot coke produced in a coke oven using a circulating gas as a heat medium. FIG. 1 shows a schematic diagram of an example of a coke dry fire extinguishing facility. In FIG. 1, the red hot coke 6 charged in the cooling tower 1 is cooled and extinguished by exchanging heat with a circulating gas 38, which is a low-temperature gas that does not contain oxygen and circulates. The circulating gas 35 that has been heated to a high temperature by cooling the red hot coke 6 is led from the cooling tower 1 through the upper flue (waste gas duct) 7 to the waste heat boiler 16, where it is heat-exchanged with the cooling water to become a low temperature. It is used again as a red hot coke cooling gas. On the other hand, the cooling water becomes steam and is used for power generation. When the red hot coke 6 is cooled, the coke is pulverized, and the circulating gas 35 contains a large amount of powdered coke as dust. When this dust (powder coke) is brought into the waste heat boiler 16 together with the circulating gas 36, the heat exchanger boiler tubes 17, 18, 19 are significantly worn. Therefore, a dust remover is generally provided in the middle of the upper flue 7 connecting the cooling tower 1 and the waste heat boiler 16. As a dust remover, a dust remover (for example, a patent) including a clogging collision type dust removal grid 8 (see, for example, Patent Document 1), a dust removal plate, and a dust hopper for collecting dust falling on the dust removal plate. Reference 2) is known.

  The dust (collected powder) collected by the dust remover is fine and relatively uniform in particle size, and can be a high-quality carbon material (carbon material). It can be sold and used outside the steelworks.

  The collected powder has a high temperature of about 900 ° C. and contains toxic CO gas. Therefore, it is cooled by the cooling pipe 11 and sealed so as not to release the circulating gas 35 out of the system. From the powder discharge pipe 10, the dust is collected in the dust remover powder storage tank 13 via a dust remover powder discharge device 12 a constituted by, for example, a rotary valve. The dust remover powder discharge pipe 10 is inserted into the cooling pipe 11 and cooled from the entire circumference of the outer peripheral portion.

The collected powder (collected powder) collected in the dust collector powder storage tank 13 is transported by a tank truck 28 or the like as a dry type (moisture content of 0 mass%) or wetted with, for example, a pug mill or the like and wetted (water content of about 15 mass%). Used for recycling.
JP-A-8-85793 (FIG. 5) JP-A-7-268339 (FIG. 2)

  As for dust in waste gas generated in coke dry fire extinguishing equipment, dry-type recovered powder is more demanding and can be sold at a higher price than wet-type, but transports dry-type powder using the system shown in FIG. In this case, the temperature of the recovered powder does not decrease, and may exhibit, for example, 200 to 300 ° C., and damage to equipment that transports and handles the recovered powder, and industrial materials with poor heat resistance such as rubber products and resin products cannot be used. There is a problem. If a rubber product, a resin product, etc. can be used for the conveyance device of the powder coke which is collect | recovered powder, it will become possible to manufacture powder coke more cheaply.

  Therefore, the object of the present invention is to solve such problems of the prior art, reduce the temperature of the dust collected by the dust remover of the coke dry fire extinguishing equipment, and recover it at a low temperature as dry recovered powder. An object of the present invention is to provide a recovery facility and a recovery method for dust collected by a dust remover of a coke dry fire extinguishing facility.

The features of the present invention for solving such problems are as follows.
(1) In the coke dry fire extinguishing equipment, the dust removal is installed below the dust remover that collects dust in the waste gas discharged from the cooling tower that cools the red hot coke and discharges the dust collected by the dust remover. A cooling device that has a dust discharge pipe and cools the outer peripheral surface of the dust remover powder discharge pipe, and a gas supply pipe that supplies stirring gas for stirring the dust in the dust remover powder discharge pipe are installed. Dust collection equipment collected by the dust remover of the coke dry fire extinguishing equipment, characterized by
(2) The length of the gas supply pipe is 40 to 60% of the length of the dust remover powder discharge pipe, and the dust collecting equipment collected by the dust remover of the coke dry fire extinguishing equipment according to (1) .
(3) When collecting the dust in the waste gas using the equipment described in (1) or (2), the supply time of the stirring gas is 1 to 10 seconds, and the supply interval is 1 to 10 minutes. A method for collecting dust collected by a dust remover of a coke dry fire extinguishing facility, characterized by being intermittently supplied as

  ADVANTAGE OF THE INVENTION According to this invention, the temperature of the dust collected with the dust remover of coke dry fire extinguishing equipment can fully be reduced, and it can collect | recover as dry powder coke collection | recovery powder. For this reason, the recovery facility is not damaged, and the recovered powder can be manufactured at a low cost.

  A method for lowering the temperature of recovered powder when dust is recovered using the coke dry fire extinguishing equipment shown in FIG. 1 will be discussed below.

  The main reason why the temperature of the recovered powder does not decrease is considered to be the low thermal conductivity of coke, which is the recovered powder. Although the thermal conductivity of coke is a function of temperature, it is approximately 3 to 5 W / m · K, and it is difficult to cool the recovered powder to the central portion of the dust remover powder discharge pipe 10.

  For example, it is conceivable to facilitate heat conduction to the inside of the dust remover powder discharge pipe 10 by reducing the diameter of the dust remover powder discharge pipe 10. However, if the diameter is reduced to such an extent that the recovered powder is sufficiently cooled, another problem arises that it becomes difficult to discharge the recovered powder.

Although a method of inserting a cooling water pipe into the dust remover powder discharge pipe 10 is also conceivable, it is extremely difficult to detect the occurrence of a hole in the cooling water pipe, and water leaks into the recovered powder due to the hole. Then, the moisture enters the circulating gas 35, 36, the steam explosion or the partial pressure of the H ₂ gas increases, and the risk of the gas explosion increases. Alternatively, the hydrogen content reacts with coal-derived sulfur to form H ₂ S gas, which causes problems such as high temperature corrosion of the boiler tubes 17, 18, and 19.

  In addition, in order to increase the cooling efficiency, it is conceivable to use a plurality of dust remover powder discharge pipes 10, for example, about three. However, in the tests conducted by the present inventors, the recovered powder is not sufficiently cooled. It was.

  Therefore, the present inventor has a method for bringing the powder coke at the center of the dust remover powder discharge pipe 10 that is difficult to transmit heat closer to the cooling pipe 11 that is a refrigerant in order to cool the powder coke that is the collected powder more efficiently. investigated. And if the powder coke could be stirred in the dust remover powder discharge pipe 10, it was thought that the temperature of the powder coke could be drastically lowered.

  However, it is extremely difficult to perform mechanical stirring because the inside of the dust remover powder discharge pipe 10 is narrow and hot. The present inventor considers that stirring using a gas injection force is highly reliable and desirable, and recalls supplying a stirring gas through a gas supply pipe. The dust remover has a dust discharge pipe installed below the dust remover that collects dust in the waste gas discharged from the cooling tower that cools the coke, and discharges the dust collected by the dust remover. A dust removing device of a coke dry fire extinguishing equipment in which a cooling device for cooling the outer peripheral surface of the powder discharge pipe and a gas supply pipe for supplying a stirring gas for stirring the dust in the dust discharger powder discharge pipe are installed. The present invention was completed as a facility for collecting collected dust.

  In the coke dry fire extinguishing equipment, as a dust remover that collects dust in the waste gas discharged from the cooling tower that cools red hot coke, the dust removal provided in the middle of the flue connecting the cooling tower and the waste heat boiler, etc. What is necessary is just to use the dust remover normally used in coke dry-type fire extinguishing facilities, such as a dust remover which consists of a board, a dust removal grid, and a dust hopper for collecting the dust which falls on a dust removal board. Moreover, what is necessary is just to use a water cooling jacket etc. for cooling of the outer peripheral surface of a dust remover powder discharge pipe.

For example, an apparatus as shown in FIG. 2 can be used as a collection facility for the dust collected by the dust remover of the coke dry fire extinguishing facility. FIG. 2 is a detailed view of the dust remover powder discharging device 12a from the dust remover hopper 9 in FIG. 1, and shows an embodiment of a collection facility for dust collected by the dust remover of the coke dry fire extinguishing facility of the present invention. . In FIG. 2, the gas supply pipe 44 is inserted into the dust remover powder discharge pipe 10, and the gas ejection nozzle 41 is provided at a position where the gas supply pipe 44 is equally divided into four in the circumferential direction at the same height position. The gas ejection nozzle 41 is provided with a nozzle hole downward to prevent blockage. The gas ejection nozzle 41 is provided in several stages in the height direction (four stages in FIG. 2). A gas pipe 42 is connected to the lower part of the gas supply pipe 44 to supply gas. As the gas, N ₂ gas is preferably used. In addition to N ₂ gas, air or the like can be used.

  It is preferable that the stirring gas is ejected instantaneously and intermittently. FIG. 3 shows a control example of the gas on-off valve 43. The dust remover powder discharger 12a is intermittently operated, stops at time t3 (valve closed), and operates at time t4 (valve opened). On the other hand, the supply of gas (stirring gas) through the gas supply pipe 44 repeats the time t1 gas ejection (for example, 2 seconds) and the time t2 gas ejection stop (for example, 5 minutes) during the time t3. The powder coke is stirred by the gas jetting power during the time when the powder coke stays at 10. The time t1 is preferably about 1 to 10 seconds, and the time t2 is preferably about 1 to 10 minutes. The gas ejection nozzle 41 is a nozzle that ejects gas downward, but the dust remover powder discharge device 12a is gas-sealed, and the gas turns to the dust remover 9 where the space exists, thereby discharging the dust remover powder. The coke at the top of the pipe 10 is also stirred, and the coke in contact with the cooling pipe 11 side is moved to replace the coke that exists near the center to increase the cooling effect. FIG. 4 shows the behavior of the powder coke in the dust remover powder discharge pipe 10. 46 is a flow of gas ejected from the gas ejection nozzle 41, and 47 is a flow of powder coke. 48 is a flow of cooling water.

  As a result of repeated experiments on the optimum value of the supply pressure of the stirring gas, the coke dry fire extinguishing equipment has a coke treatment amount of about 100 t / hour, the diameter of the dust remover powder discharge pipe 10 is 300 mm, and the gas supply pipe 44 When the diameter was 50 mm, it was found that about 196 kPa was optimum. If the gas supply pressure is too high, the recovered powder is wound up and re-scattered in the circulating gas, which is not preferable. If the gas supply pressure is too low, the stirring effect is not sufficient. The effect of the agitation also depends on the gas ejection time (t1). By appropriately setting the gas supply pressure and the gas ejection time, the recovered powder can be sufficiently agitated and re-scattering can be prevented.

  When paying attention to the re-scattering of the recovered powder, the total length of the gas supply pipe 44 is preferably about half of the total length of the dust remover powder discharge pipe 10. Even if the gas supply pipe 44 is not provided over the entire length of the dust remover powder discharge pipe 10, the stirring effect and the cooling effect thereby are sufficient. If the gas supply pipe 44 is too long, re-scattering of the collected powder may be a problem. Therefore, the length of the gas supply pipe 44 is preferably 40 to 60% of the length of the dust remover powder discharge pipe 10.

  Furthermore, when the dust collector hopper lower limit level meter 39 of the dust remover hopper 9 is activated, a sequence is set so that the dust remover powder discharging device 12a stops (valve closes), and the amount of collected powder stored in the dust remover powder discharge pipe 10 is set. If the lower limit is limited, it is possible to prevent re-scattering of the recovered powder, which occurs due to a small storage amount.

An operation test using the coke dry fire extinguishing equipment shown in FIGS. 1 and 2 was performed, and the dust collected by the dust remover was collected. The dust temperature in the dust remover hopper 9 was 900 ° C. The dust remover powder discharger 12a is composed of a rotary valve. As an intermittent operation, in FIG. 3, the valve was closed and stopped for a time t3 = 2 hours, and the valve was opened for a time t4 = 20 minutes. When N ₂ gas was not supplied through the gas supply pipe 44, the temperature of the dust (powder coke) discharged from the dust remover powder discharger 12a was 300 ° C. (comparative example).

Next, the gas on-off valve 43 was controlled, and N ₂ gas was blown from the gas supply pipe 44. The control of the gas on-off valve 43 is as follows: during time t3 in FIG. 3, time t1 = 2 seconds gas ejection, time t2 = 5 minutes gas ejection stop is repeated, and powder coke stays in the dust remover powder discharge pipe 10. During the time t3, the powder coke was stirred by the gas jet power. In this case, the temperature of the dust (powder coke) discharged from the dust remover powder discharging device 12a was 150 ° C. (example of the present invention). Therefore, the powder coke can be transported using a device using a rubber product or a resin product, and the transport device is not damaged.

  FIG. 5 shows the temperature distribution of dust (powder coke) in the dust remover powder discharge pipe 10 during the above operation. According to FIG. 5, in the comparative example, the central portion of the dust remover powder discharge pipe 10 is not cooled and remains at a high temperature, but in the present invention example, the temperature distribution is gentle in the radial direction of the dust remover powder discharge pipe 10, It turns out that the powder coke is cooled as a whole.

Schematic which shows an example of a coke dry-type fire extinguishing equipment. Schematic which shows one Embodiment of the collection | recovery equipment of the dust collected with the dust remover of the coke dry fire extinguishing equipment of this invention. The example of control of a gas on-off valve. The figure which shows the behavior of the powder coke in a duster powder discharge pipe. The figure which shows the temperature distribution of the dust in a dust remover powder discharge pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling tower 2 Circular flue 3 Bucket 4 Hoisting machine 5 Inlet 6 Red hot coke 7 Upper flue (waste gas duct)
DESCRIPTION OF SYMBOLS 8 Dust removal grid 9 Dust removal hopper 10 Dust removal powder discharge pipe 11 Cooling pipe 12a, b Dust removal powder discharge device 13 Dust removal powder storage tank 14 Cooling water inlet pipe 15 Cooling water outlet pipe 16 Waste heat boiler 17 Boiler tube 18 Boiler tube DESCRIPTION OF SYMBOLS 19 Boiler tube 20 Steam drum 21 Deaerator 22 Boiler feed water pump 23 Boiler circulating water pump 24 Lower flue 25 Cyclone 26a, b Cyclone powder discharge device 27 Dust collector powder storage tank 28 Tank lorry vehicle 29a, b Suction hose 30 for powder collection Circulating fan 31 Gas blowing device 32a, b Cut-off valve 33a, b Cut-out gate 34 Cooling coke transport conveyor 35 Circulating gas 36 Circulating gas 37 Circulating gas 38 Circulating gas 39 Dust remover hopper lower limit level meter 40 Dust remover hopper emergency lower limit level meter 41 Gas ejection nozzle 2 Gas pipe 43 gas on-off valve 44 the gas supply tube 45 Gas 46 Gas flow 48 cooling water flow 47 coke of

Claims (3)

  In a coke dry fire extinguishing system, a dust remover powder discharge pipe is installed below the dust remover that collects dust in the waste gas discharged from the cooling tower that cools the red hot coke, and discharges the dust collected by the dust remover. A cooling device for cooling the outer peripheral surface of the dust remover powder discharge pipe, and a gas supply pipe for supplying a stirring gas for stirring the dust is installed in the dust remover powder discharge pipe. A collection facility for dust collected by the dust remover of the coke dry fire extinguishing facility.   The length of the gas supply pipe is 40 to 60% of the length of the dust remover powder discharge pipe, and the equipment for collecting dust collected by the dust remover of the coke dry fire extinguishing equipment according to claim 1.   When collecting the dust in the waste gas using the facility according to claim 1 or 2, the stirring gas is supplied for 1 to 10 seconds and the supply interval is set to 1 to 10 minutes intermittently. A method for recovering dust collected by a dust remover of a coke dry fire extinguishing system, characterized in that it is supplied.

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